@inproceedings{AltenbergerNallaNosteretal., author = {Altenberger, Igor and Nalla, Ravi K. and Noster, Ulf and Liu, G.Y. and Scholtes, Berthold and Ritchie, Robert O.}, title = {Effects of Deep Rolling on the Fatigue Behavior of Ti-6Al-4V at Ambient and Elevated Temperatures}, series = {Ti-2003 Science and Technology, Proceedings of the 10th World Conference on Titanium, held at the CCH-Congress Center Hamburg, Germany 13-18 July 2003, Vol 1}, booktitle = {Ti-2003 Science and Technology, Proceedings of the 10th World Conference on Titanium, held at the CCH-Congress Center Hamburg, Germany 13-18 July 2003, Vol 1}, editor = {L{\"u}tjering, G. and Albrecht, J.}, publisher = {Wiley}, organization = {Wiley}, isbn = {3-527-30306-5}, pages = {1059 -- 1066}, language = {en} } @inproceedings{AltenbergerNosterNallaetal., author = {Altenberger, Igor and Noster, Ulf and Nalla, Ravi K. and Ritchie, Robert O. and Scholtes, Berthold}, title = {Residual stress relaxation in fatigue of mechanically surface treated materials}, series = {Proceedings 132nd Annual TMS Meeting, March 2-6, 2003, San Diego, California}, booktitle = {Proceedings 132nd Annual TMS Meeting, March 2-6, 2003, San Diego, California}, pages = {312}, language = {en} } @inproceedings{AltenbergerNallaNosteretal., author = {Altenberger, Igor and Nalla, Ravi K. and Noster, Ulf and Scholtes, Berthold and Ritchie, Robert O.}, title = {On the fatigue behavior and associated effect of residual stresses in deep rolled and laser shock peened Ti-6Al-4V at ambient and elevated temperatures}, series = {2003 TMS annual meeting}, booktitle = {2003 TMS annual meeting}, publisher = {The Minerals, Metals \& Materials Society (TMS)}, pages = {359}, abstract = {Mechanical surface treatments, such as deep rolling, shot peening and laser shock peening, can significantly improve the fatigue behavior of highly stressed metallic components. Deep rolling is an especially attractive technique since it is possible to generate deep, near-surface compressive residual stresses and work hardening while retaining a relatively smooth surface finish. Indeed, this technique is best known for increasing the fatigue strength and lifetime of steel components such as crankshafts. Although most work on deep rolling has been on steels, recently it has also been applied with reasonable success to titanium alloys. Accordingly, in this investigation, we examine the effect of deep rolling on the high-cycle fatigue behavior of Ti-6Al-4V, with particular emphasis on the thermal and mechanical stability of the residual stress states and near-surface microstructures. Preliminary results on laser shock peened Ti-6Al-4V are also presented for comparison. In addition, we examine whether these surface treatments are effective in retaining fatigue strength at the higher temperatures of 300 to 450C. Based on the cyclic deformation and stress/life behavior, together with the X-ray and microstructural observations, it is found that deep rolling can be quite effective in retarding the initiation and initial propagation of fatigue cracks in Ti-6Al-4V at such higher temperatures, despite the almost complete relaxation of the residual stresses at the surface. This clearly implies that, in addition to residual stresses, near-surface microstructures, which in Ti-6Al-4V consist of ultrafine near-surface nanostructures, play a critical role in the enhancement of fatigue lifetimes by mechanical surface treatments.}, language = {en} } @inproceedings{JuijermAltenbergerNosteretal., author = {Juijerm, Patiphan and Altenberger, Igor and Noster, Ulf and Scholtes, Berthold}, title = {Residual stress relaxation and cyclic deformation behavior of deep rolled AlMg4.5Mn (AA5083) at elevated temperatures}, series = {Materials Science Forum}, volume = {490-491}, booktitle = {Materials Science Forum}, publisher = {Trans Tech Publications}, doi = {10.4028/www.scientific.net/MSF.490-491.436}, pages = {436 -- 441}, abstract = {The cyclic deformation behavior of deep rolled and polished aluminium wrought alloy AlMg4,5Mn in the temperature range 20-300°C has been investigated. Results of quasistatic tension and compression tests of untreated specimens in the temperature range 20-300°C are presented. To characterize the fatigue behavior for stress-controlled tests as a function of test temperature, s-n curves, cyclic deformations curves and mean strains as a function of number of cycles are given. The residual stress- and work hardening states near the surface of deep rolled aluminium alloy AlMg4.5Mn before and after fatigue tests were investigated by X-ray diffraction methods. The investigated AlMn4.5Mn aluminium alloy shows cyclic hardening until fracture at all stress amplitudes in stress-controlled fatigue tests at 25-150°C. With increasing temperature the deformation behavior shifts from cyclic hardening to cyclic softening. Below a certain stress amplitude at a given temperature deep rolling led to a reduction of the plastic strain amplitude as compared to the untreated state through cyclically stable near-surface work hardening as indicated by stable FWHM-values. This reduction in plastic strain amplitude is associated with enhanced fatigue lives. The effectiveness of deep rolling is governed by the cyclic and thermal stability of near-surface work hardening rather than macroscopic compressive residual stresses. Since near-surface work hardening is known to retard crack initiation, deep rolling is also effective in temperature- and stress ranges where macroscopic compressive residual stresses have relaxed almost completely, but where near-surface work hardening prevails. Above certain stress amplitudes and temperatures, deep rolling has no beneficial effect on the fatigue behavior of AlMg4.5Mn. This is a consequence of instable near-surface microstructures, especially instable near-surface work hardening.}, language = {en} } @inproceedings{NonnVoelling, author = {Nonn, Aida and V{\"o}lling, Alexander}, title = {Lokale Spannungsanalyse bei Rissinitiierung}, series = {4. Workshop Kompetenzverbund Kerntechnik "Komponentensicherheit und Werkstoffverhalten", MPA Stuttgart, Germany}, booktitle = {4. Workshop Kompetenzverbund Kerntechnik "Komponentensicherheit und Werkstoffverhalten", MPA Stuttgart, Germany}, subject = {Rissverhalten}, language = {en} } @inproceedings{NonnDahlBleck, author = {Nonn, Aida and Dahl, Winfried and Bleck, Wolfgang Peter}, title = {Damage Modelling and Safety Assessment of the Hybrid Welded Structures}, series = {5th German-Japanese Seminar "Materials, Processes and Components", Fraunhofer Institute for Mechanics of Materials, Freiburg, Germany}, booktitle = {5th German-Japanese Seminar "Materials, Processes and Components", Fraunhofer Institute for Mechanics of Materials, Freiburg, Germany}, language = {en} } @inproceedings{Dendorfer, author = {Dendorfer, Sebastian}, title = {How much iron to pump? The determination of muscle forces for activities of daily living}, series = {DGU, Berlin, 2008}, booktitle = {DGU, Berlin, 2008}, language = {en} } @inproceedings{HammerDendorfer, author = {Hammer, Joachim and Dendorfer, Sebastian}, title = {Cyclic loading and microstructure of cancellous bone}, series = {Journal of Biomechanics}, volume = {41}, booktitle = {Journal of Biomechanics}, number = {Suppl. 1, July 2008}, doi = {10.1016/S0021-9290(08)70409-3}, pages = {S410}, language = {en} } @inproceedings{UcsnikGradingerNosteretal., author = {Ucsnik, Stephan A. and Gradinger, Rudolf and Noster, Ulf and Pahr, Dieter H.}, title = {Finite element based optimization of a novel metal-composite-joint}, series = {1st EUCOMAS, European Conference on Materials and Structures in Aerospace, Conference Berlin, May 26 - 27, 2008 }, booktitle = {1st EUCOMAS, European Conference on Materials and Structures in Aerospace, Conference Berlin, May 26 - 27, 2008 }, publisher = {VDI-Verlag}, address = {D{\"u}sseldorf}, issn = {0083-5560}, pages = {371 -- 379}, abstract = {Aerospace and automotive industries employ three main techniques to set up joints between metal and fibre reinforced plastics parts (FRP); adhesive bonding, mechanical fastening with rives/bolts and a hybrid combination. A new joint technique has been developed to combine the two advantageous mechanisms form-closure and adhesion in a fibre-friendly way. Prior is established through metal structures (pins) which are perpendicularly welded onto metal surfaces with an arc-welding-process. They intrude into the FRP during lay-up and therefore set up a first connection. The composite-matrix is responsible for latter adhesive bonding and final form closure. Finite-element-analyses of cylindrically shaped joints are carried out to get detailed knowledge of the influence of parameters like pin-number, pin-position, pin-height, pin-form sleeve-geometry, and stiffness behaviour. Long calculation times of 3D-models lead to the introduction of a corresponding 2D-axisymmetric-model which is used to run parameter-studies within a reasonable time. For this novel technique the combination of fibre-friendly form closure and adhesive bonding of interface plays a major role. A well selected amount of vertical reinforcements, their placement and geometrical dimensions will lead to a stiffer joint. Goal is to minimize fibre-deletion and overlap length to improve load-transfer and joint-strength, to reduce weight in high-strength-applications as well as the avoidance of safety rivets.}, language = {en} } @inproceedings{AndersendeZeeDendorferetal., author = {Andersen, Michael Skipper and de Zee, Mark and Dendorfer, Sebastian and MacWilliams, Bruce and Rasmussen, John}, title = {Validation of a detailed lower extremity model based on the Klein Horsman data set}, series = {Proceedings of the 12th International Symposium on Computer Simulation in Biomechanics (ISB 2009), July 2nd - 4th 2009, Cape Town, South Africa}, booktitle = {Proceedings of the 12th International Symposium on Computer Simulation in Biomechanics (ISB 2009), July 2nd - 4th 2009, Cape Town, South Africa}, pages = {27 -- 28}, language = {en} } @inproceedings{DendorferCarbesRasmussen, author = {Dendorfer, Sebastian and Carbes, S. and Rasmussen, John}, title = {The influence of muscle forces on biomechanical fracture fixation simulations - from in-vivo forces to tissue strains}, series = {World Congress on Medical Physics and Biomedical Engineering, 7 - 12, 2009, Munich}, booktitle = {World Congress on Medical Physics and Biomedical Engineering, 7 - 12, 2009, Munich}, language = {en} } @inproceedings{DendorferRasmussen, author = {Dendorfer, Sebastian and Rasmussen, John}, title = {The influence of in-vivo muscle forces on the stress distribution in a vertebral body during activities of daily living}, series = {Eurospine Warsaw, Poland 2009}, booktitle = {Eurospine Warsaw, Poland 2009}, language = {en} } @inproceedings{Dendorfer, author = {Dendorfer, Sebastian}, title = {Biomechanical evaluation and optimisation of countermeasure exercises}, series = {ESA/ESTEC Bedrest Strategy Workshop, Noordwijk, NL, 2009}, booktitle = {ESA/ESTEC Bedrest Strategy Workshop, Noordwijk, NL, 2009}, language = {en} } @inproceedings{DendorferEnglert, author = {Dendorfer, Sebastian and Englert, Carsten}, title = {Forces on a clavicles midshaft fracture and influence of fracture type}, series = {AO Symposium, Regensburg, 2009}, booktitle = {AO Symposium, Regensburg, 2009}, language = {en} } @inproceedings{KrenkelPennecotLenzetal., author = {Krenkel, Lars and Pennecot, Julien and Lenz, Christian and Feldmann, Daniel and Wagner, Claus}, title = {Optimierung der Hochfrequenz-Oszillationsventilation mittels str{\"o}mungsmechanischer Methoden und kontrastgasgest{\"u}tzter Magnetresonanztomografie - Teilprojekt: Rekonstruktion von Geometrien aus medizinischen Bilddaten und Erstellung von Modellen f{\"u}r experimentelle Str{\"o}mungsuntersuchungen}, series = {Laseranwendung in der Medizin, Erfassen und Verarbeiten kardiovaskul{\"a}rer Signale, protektive Beatmungskonzepte : 3. Dresdner Medizintechnik-Symposium - mit DFG-Forschungsschwerpunkt Protektive Beatmungskonzepte, 6. bis 9. Dezember 2010, Dresden}, booktitle = {Laseranwendung in der Medizin, Erfassen und Verarbeiten kardiovaskul{\"a}rer Signale, protektive Beatmungskonzepte : 3. Dresdner Medizintechnik-Symposium - mit DFG-Forschungsschwerpunkt Protektive Beatmungskonzepte, 6. bis 9. Dezember 2010, Dresden}, editor = {F{\"u}ssel, Jens and Koch, Edmund and Malberg, Hagen}, publisher = {TUDpress}, address = {Dresden}, isbn = {978-3-942710-02-2}, pages = {107 -- 114}, abstract = {Der vorliegende Artikel skizziert die neu entwickelte Prozesskette f{\"u}r detailgenaue Rekonstruktion von Geometrien anhand medizinischer Bilddaten sowie die Herstellung von transparenten Modellen f{\"u}r experimentelle Untersuchungen mit bildgebenden Str{\"o}mungsmessverfahren. Die Geometriedaten und Modelle werden f{\"u}r systematische Untersuchungen der komplexen Transportvorg{\"a}nge in den Atemwegen bei k{\"u}nstlicher Beatmung mittels Hochfrequenzoszillationsventilation (HFOV) verwendet.}, language = {en} } @inproceedings{DendorferRasmussenChristensenetal., author = {Dendorfer, Sebastian and Rasmussen, John and Christensen, Soeren Toerholm and Robie, Bruce}, title = {The Effect of Spinal Disc Herniation on Multifidus Muscles}, series = {56th Orthopaedic Research Society Meeting, New Orleans, USA, 2010}, booktitle = {56th Orthopaedic Research Society Meeting, New Orleans, USA, 2010}, language = {en} } @inproceedings{RobieRasmussenChristensenetal., author = {Robie, Bruce and Rasmussen, John and Christensen, Soeren Toerholm and Dendorfer, Sebastian}, title = {Herniation Induces 55\% Increase in Load of Key Stabilizing Muscle - Impact on Herniation Treatment Devices?}, series = {Spine Arthoplasty Society Meeting, New Orleans, 2010}, booktitle = {Spine Arthoplasty Society Meeting, New Orleans, 2010}, language = {en} } @inproceedings{NonnKalwa, author = {Nonn, Aida and Kalwa, Christoph}, title = {Modeling of damage behavior of high strength pipeline steel}, series = {18th European Conference on Fractur: Fracture of Materials and Structures from Micro to Macro Scale, August 30 - September 03, 2010, Dresden, Germany}, booktitle = {18th European Conference on Fractur: Fracture of Materials and Structures from Micro to Macro Scale, August 30 - September 03, 2010, Dresden, Germany}, language = {en} } @inproceedings{Nonn, author = {Nonn, Aida}, title = {Failure modeling of hybrid-laser welds in transition temperature region}, series = {18th European Conference on Fracture, Fracture of Materials and Structures from Micro to Macro Scale, August 30 - September 03, 2010 Dresden, Germany}, booktitle = {18th European Conference on Fracture, Fracture of Materials and Structures from Micro to Macro Scale, August 30 - September 03, 2010 Dresden, Germany}, address = {Dresden}, language = {en} } @inproceedings{NonnErdelenPepplerKalwa, author = {Nonn, Aida and Erdelen-Peppler, Marion and Kalwa, Christoph}, title = {Numerical and experimental investigation of the influence of HAZ on the fracture behavior of longitudinal welded linepipes}, series = {18th European Conference on Fracture, Fracture of Materials and Structures from Micro to Macro Scale, Dresden, Germany}, booktitle = {18th European Conference on Fracture, Fracture of Materials and Structures from Micro to Macro Scale, Dresden, Germany}, abstract = {The present paper deals with the influence of heat affected zone (henceforth HAZ) on the fracture performance of longitudinal welded linepipes in dependence on constraint level. It has been shown that toughness values of HAZ obtained from standard fracture mechanics tests lead to uneconomic linepipe design for two reasons. The first reason is that laboratory specimens with higher constraint level generally exhibit lower fracture resistance compared to flawed linepipes. The second one has to do with a higher probability of cleavage failure occurrence in the laboratory specimen than in the linepipes due to larger areas of lower toughness (so called local brittle zones (LBZ)) intersected by crack front. In recent years numerous studies have been initiated with the objective to quantify the constraint level and thus to allow for less conservative linepipe safety assessment by applying constraint corrected toughness values. However, the main focus of these studies has hitherto been on the homogeneous materials, failing to account for the possible effects of different microstructures within the heterogeneous HAZ. This paper seeks to close this gap by reporting on results from tests on fracture mechanics specimens of a high strength X80 steel, i.e. SENB and SENT specimens as well as results from ring expansion tests. Both, deep and shallow cracks are inserted in the fracture mechanics specimens and rings targeting the fusion line (FL). By varying the initial crack size and sample type, different constraint levels are achieved and subsequently quantified using numerical methods. Besides constraint observations, post metallographic analyses are performed to identify exact HAZ microstructure involved at the crack tip. Finally, the influence of HAZ properties, flaw size and geometry on the failure behaviour of the linepipes has been demonstrated and assessed. Based on the combination of the results from constraint studies and the post metallographic analyses, the methodology is proposed which enables simple quantitative prediction of toughness values for safe and economic design of linepipes with flaws located in HAZ.}, language = {en} } @inproceedings{SchlechtSchulzeRosenloecheretal., author = {Schlecht, Berthold and Schulze, T. and Rosenl{\"o}cher, T. and Schulz, Carsten}, title = {Untersuchung von Großantrieben im Multi-Megawatt-Bereich mit Hilfe der Mehrk{\"o}rpersystem-Simulation und der Finite-Elemente-Methode als Basis f{\"u}r die Betriebsfestigkeitsrechnung}, series = {AKIDA, Aachener Kolloquium f{\"u}r Instandhaltung, Diagnose und Anlagen{\"u}berwachung, 17./18. November 2010 : Tagungsband zum 8. Aachener Kolloquium f{\"u}r Instandhaltung, Diagnose und Anlagen{\"u}berwachung}, booktitle = {AKIDA, Aachener Kolloquium f{\"u}r Instandhaltung, Diagnose und Anlagen{\"u}berwachung, 17./18. November 2010 : Tagungsband zum 8. Aachener Kolloquium f{\"u}r Instandhaltung, Diagnose und Anlagen{\"u}berwachung}, publisher = {Zillekens}, address = {Stolberg}, isbn = {978-3-941277-08-3}, pages = {371 -- 380}, language = {de} } @inproceedings{SchlechtSchulzRosenloecheretal., author = {Schlecht, Berthold and Schulz, Carsten and Rosenl{\"o}cher, T. and Schulze, T.}, title = {Untersuchung und Optimierung des dynamischen Verhaltens von Schaufelradantrieben}, series = {AKIDA, Aachener Kolloquium f{\"u}r Instandhaltung, Diagnose und Anlagen{\"u}berwachung, 17./18. November 2010 : Tagungsband zum 8. Aachener Kolloquium f{\"u}r Instandhaltung, Diagnose und Anlagen{\"u}berwachung}, booktitle = {AKIDA, Aachener Kolloquium f{\"u}r Instandhaltung, Diagnose und Anlagen{\"u}berwachung, 17./18. November 2010 : Tagungsband zum 8. Aachener Kolloquium f{\"u}r Instandhaltung, Diagnose und Anlagen{\"u}berwachung}, publisher = {Zillekens}, address = {Stolberg}, isbn = {978-3-941277-08-3}, pages = {363 -- 370}, language = {de} } @inproceedings{UlbrichGalkaGuenthner, author = {Ulbrich, Alexander and Galka, Stefan and G{\"u}nthner, Willibald A.}, title = {Secure planning of order picking systems with the aid of simulation}, series = {Proceedings of th 43rd Hawaii International Conference on System Sciences (HICSS), 5-8 Jan. 2010, Koloa, Kauai, Hawaii}, booktitle = {Proceedings of th 43rd Hawaii International Conference on System Sciences (HICSS), 5-8 Jan. 2010, Koloa, Kauai, Hawaii}, publisher = {IEEE}, address = {Piscataway, NJ}, isbn = {978-0-7695-3869-3}, issn = {1530-1605}, doi = {10.1109/HICSS.2010.326}, pages = {1 -- 7}, abstract = {Planning a new logistics center is a quite difficult job. Depending on the requirements there are a great number of possible design versions. The planner has to consider not only the present but also the future requirements. Up to now, the planner decides on the basis of experience which system will perform the requested services best. This paper illustrates the redesign of a new order-picking system in industry supported by a simulation tool of our institute designed especially for the rough planning. With the described project the road capability of the applied simulation concept is underlined. Several versions based on the requirements were investigated and evaluated. Key figures are calculated and a recommendation depending on performance and arising expenses is given.}, language = {de} } @inproceedings{GalkaGuenthnerUlbrich, author = {Galka, Stefan and G{\"u}nthner, Willibald A. and Ulbrich, Alexander}, title = {Planning of order-picking-systems with support of discrete simulation}, series = {Logistics and Supply Chain Management: Deutsch-Russische Perspektiven. Proceedings of the 5th German-Russian Logistics Workshop (DR-LOG10)}, booktitle = {Logistics and Supply Chain Management: Deutsch-Russische Perspektiven. Proceedings of the 5th German-Russian Logistics Workshop (DR-LOG10)}, language = {en} } @inproceedings{EnglertMuellerDendorfer, author = {Englert, Carsten and M{\"u}ller, F. and Dendorfer, Sebastian}, title = {Einfluss der Muskelkr{\"a}fte, des Bewegungsausmaßes und der Bruchform auf die Kraft{\"u}bertragung des Implantat-Knochenverbundes am Beispiel der Claviculafraktur im mittleren Drittel}, series = {17. Jahreskongress der Deutschen Vereinigung f{\"u}r Schulter- und Ellenbogenchirurgie (DVSE), Rosenheim 2010}, booktitle = {17. Jahreskongress der Deutschen Vereinigung f{\"u}r Schulter- und Ellenbogenchirurgie (DVSE), Rosenheim 2010}, abstract = {Fragestellung Es soll in dieser Computersimulationsstudie untersucht werden, wie der Osteosyntheseverbund Platte mit Schrauben im Verbund mit einer im mittleren Drittel gebrochenen Clavicula durch das Bewegungsausmaß in vivo belastet ist. Was sind die grundlegenden Kr{\"a}fte die auf Clavicula und Implantat wirken und welchen Einfl uss hat die Bruchform. Methodik Die Muskel- und Gelenkkr{\"a}fte sowie die Belastung des Implantatverbundes wurden mit einer muskuloskelletalen Simulationssoftware (AnyBody Technology, V.4) berechnet. Hierf{\"u}r wurden mit einem komplexen Model des menschlichen K{\"o}rpers folgende Bewegungen analysiert: eine Flexion von 160° und Abduktion 160° mit einem Gewicht von 2 kg in der Hand. Aus CT-Patientendaten wurden zwei dreidimensionale Modelle des Clavicula-Implantat Verbundes gebildet, die sich in der Frakturform unterscheiden (Querfraktur und vertikale Fraktur). In beiden Modellen wurde eine Claviculaosteosynthese in superiorer Position mit einer 6 Loch LCP mit 2 Schrauben pro Hauptfragment verwendet. Die Materialeigenschaften wurden aus der Dichte des Materials sowie aus Literaturdaten verwendet. Die Muskel- und Gelenkkr{\"a}fte aus der muskuloskelletalen Berechnung wurden auf das Finite Elemente Modell {\"u}bertragen und die Spannungen und Dehnungen des Implantat-Knochenverbundes wurden berechnet. Ergebnisse Es zeigte sich, dass die simulierte in vivo Belastung stark abh{\"a}ngig vom Flexionswinkel ist. Das Implantat ist in der superioren Lage auf Biegung belastet, welche maximale Werte im {\"U}berschulterniveau erreicht. Die Bruchform mit anatomischer Reposition und Kontakt der Hauptfragmente zueinander f{\"u}hrt zu einer deutlichen Entlastung des Osteosyntheseverbundes im Vergleich zu einer Bruchform mit vertikaler Fraktur. Schlussfolgerung Aus den Analysen ist eine Positionierung der Plattenosteosynthese f{\"u}r die im mittleren Drittel frakturierte Clavicula in anterior-superiorer Lage w{\"u}nschenswert. Die anatomische Reposition entlastet den Osteosyntheseverbund und sollte m{\"o}glichst erreicht werden. Die Nachbehandlung sollte ein Bewegungsausmaß f{\"u}r den Arm f{\"u}r 4 Wochen f{\"u}r einfache Bruchformen auf 70° Flexion und Abduktion limitieren und f{\"u}r komplexe Bruchformen diese Limitierung ausgedehnt werden.}, language = {de} } @inproceedings{KrenkelWagnerWolfetal., author = {Krenkel, Lars and Wagner, Claus and Wolf, Ursula and Scholz, Alexander-Wigbert K. and Terekhov, Maxim and Rivoire, Julien and Schreiber, W.}, title = {Protective Artificial Lung Ventilation: Impact of an Endotracheal Tube on the Flow in a Generic Trachea}, series = {New Results in Numerical and Experimental Fluid Mechanics VII : Contributions to the 16th STAB/DGLR Symposium Aachen, Germany 2008}, booktitle = {New Results in Numerical and Experimental Fluid Mechanics VII : Contributions to the 16th STAB/DGLR Symposium Aachen, Germany 2008}, editor = {Hirschel, Ernst Heinrich and Schr{\"o}der, Wolfgang and Fujii, Kozo and Haase, Werner and Leer, Bram and Leschziner, Michael A. and Pandolfi, Maurizio and Periaux, Jacques and Rizzi, Arthur and Roux, Bernard and Shokin, Yurii I. and Dillmann, Andreas and Heller, Gerd and Klaas, Michael and Kreplin, Hans-Peter and Nitsche, Wolfgang}, publisher = {Springer Berlin Heidelberg}, address = {Berlin, Heidelberg}, isbn = {978-3-642-14242-0}, doi = {10.1007/978-3-642-14243-7_62}, pages = {505 -- 512}, abstract = {Computational Fluid Dynamics (CFD) and experimental investigations on a generic model of the trachea have been carried out focusing on the impact of an endotracheal tube (ETT) on the resulting flow regime. It could be shown that detailed modelling of the airway management devices is essential for proper flow prediction, but secondary details as Murphy Eyes can be neglected. Models with bending and connector promote the formation of stronger secondary flows and disturbances which persist for a longer time.}, language = {en} } @inproceedings{WeberDendorferRenkawitzetal., author = {Weber, Tim and Dendorfer, Sebastian and Renkawitz, Tobias and Dullien, Silvia and Grifka, Joachim}, title = {Clinical gait analysis combined with musculoskeletal modelling - coding a new generation of evaluation instruments}, series = {Deutsche Gesellschaft f{\"u}r Biomechanik, Murnau, 2011}, booktitle = {Deutsche Gesellschaft f{\"u}r Biomechanik, Murnau, 2011}, language = {en} } @inproceedings{PutzerWeberDendorfer, author = {Putzer, Michael and Weber, Tim and Dendorfer, Sebastian}, title = {Design studies on hip prosthesis using patient specific data}, series = {Simpleware Users meeting, November 9th 2011, Bristol, UK}, booktitle = {Simpleware Users meeting, November 9th 2011, Bristol, UK}, language = {en} } @inproceedings{Dendorfer, author = {Dendorfer, Sebastian}, title = {The effect of multifidus muscles atrophy following disc herniation on disc loading}, series = {Deutsche Gesellschaft f{\"u}r Biomechanik, Murnau, 2011}, booktitle = {Deutsche Gesellschaft f{\"u}r Biomechanik, Murnau, 2011}, language = {en} } @inproceedings{GalibarovAlMunajjedDendorferetal., author = {Galibarov, Pavel E. and Al-Munajjed, Amir Andreas and Dendorfer, Sebastian and Christensen, Soeren Toerholm and Rasmussen, John}, title = {The effect of varying the stiffness of spinal fusion devices on the adjacent levels using multibody dynamics simulation}, series = {Orthopaedic Proceedings}, volume = {94-B}, booktitle = {Orthopaedic Proceedings}, number = {SUPP_XL01 Sep 2012}, pages = {2}, abstract = {INTRODUCTION Several clinical studies demonstrated long-term adjacent-level effects after implantation of spinal fusion devices[1]. These effects have been reported as adjacent joint degeneration and the development of new symptoms correlating with adjacent segment degeneration[2] and the trend has therefore gone to motion preservation devices; however, these effects have not been understood very well and have not been investigated thoroughly[3]. The aim of this study is to investigate the effect of varying the stiffness of spinal fusion devices on the adjacent vertebral levels. Disc forces, moments and facet joint forces were analyzed. METHODS The AnyBody Modeling System was used to compute the in-vivo muscle and joint reaction forces of a musculoskeletal model. The full body model used in this study consists of 188 muscle fascicles in the lumbar spine and more than 1000 individual muscle branches in total. The model has been proposed by de Zee et al.[3], validated by Rasmussen et al.[4] and by Galibarov et al.[5]. The new model[5] determines the individual motions between vertebrae based on the equilibrium between forces acting on the vertebrae from muscles and joints and the passive stiffness in disks and ligaments, figure 1a. An adult of 1.75 m and 75 kg with a spinal implant in L4L5 was modeled. This model was subjected to a flexion-extension motion using different elastic moduli to analyze and compare to a non-implanted scenario. The analyzed variables were vertebral motion, the disc reaction forces and moments, as well as facet joint forces in the treated and the adjacent levels: L2L3, L3L4, L4L5 and L5-Sacrum. RESULTS When introducing a spinal fusion device in the L4L5 joint the reaction forces and moments decreased in this joint with stiffer devices leading to lower joint loads. However, in the adjacent joints, L3L4 and L5Sacrum, an increase was observed when implanting stiffer devices. Similar trends could be found for the L2L3 joint. The loads in the facet joints showed the same trends. While introducing a spinal fusion device reduced the facet joint forces in the treated joint, the loads in the adjacent facet joints were increased according to the stiffness of the implanted device, figure 1b. DISCUSSION While the treated disc joint showed reduced motion and loads, the adjacent levels demonstrated a significant increase. In particular, the increased facet joint forces in the adjacent levels can lead to adjacent level facet pain or accelerated facet joint degeneration. Introducing a device resulted in preventing facet contact and therefore facet joint loads, even using the device with the lowest stiffness. CONCLUSION The presented model shows that clinical complications such as facet joint degeneration in adjacent levels after implantation of spinal fusion device are consistent with the change in the mechanical-stimulus distribution in the system.}, language = {en} } @inproceedings{GalibarovDendorferChristensen, author = {Galibarov, Pavel E. and Dendorfer, Sebastian and Christensen, Soeren Toerholm}, title = {On modelling spine curvature dependent on muscular and external forces in multibody dynamics system}, series = {International Society of Biomechanics (ISB), 13th congress, 2011, Brussels, Belgium}, booktitle = {International Society of Biomechanics (ISB), 13th congress, 2011, Brussels, Belgium}, pages = {2}, abstract = {This paper presents a computational approach for investigating effect of muscular and external forces on curvature of the lumbar spine. Multibody dynamics system is used to compute the lumbar spine curvature using a force-dependent kinematics facility, e.g. this method allows releasing some degrees of freedom in order to be computed based on the current load configuration.}, language = {en} } @inproceedings{RasmussenBichlerChristensenetal., author = {Rasmussen, John and Bichler, R. and Christensen, Soeren Toerholm and Wirix-Speetjens, Roel and Dendorfer, Sebastian and Renkawitz, Tobias}, title = {Subject-specific Musculoskeletal Simulation of Hip Dislocation Risk in Activities of Daily Living}, series = {Proceedings of the 2011 ORS Annual Meeting, Long Beach, CA.}, booktitle = {Proceedings of the 2011 ORS Annual Meeting, Long Beach, CA.}, number = {Paper No. 306}, language = {en} } @inproceedings{RobieDendorferRasmussenetal., author = {Robie, Bruce and Dendorfer, Sebastian and Rasmussen, John and Christensen, Soeren Toerholm}, title = {Axial Rotation Requires Greatest Load in Multifidus Muscle - Potential Association with Low Back Pain?}, series = {Annual Meeting of the AANS/CNS Section on Disorders of the Spine and Peripheral Nerves, 2011, Phoenix, Arizona}, booktitle = {Annual Meeting of the AANS/CNS Section on Disorders of the Spine and Peripheral Nerves, 2011, Phoenix, Arizona}, language = {en} } @inproceedings{GalibarovDendorferRasmussen, author = {Galibarov, Pavel E. and Dendorfer, Sebastian and Rasmussen, John}, title = {Two Computational Models of the Lumbar Spine:}, series = {Proceedings of the 2011 ORS Annual Meeting, Long Beach, CA, vol. Marie Curie Initial Training Network "SpineFX"}, booktitle = {Proceedings of the 2011 ORS Annual Meeting, Long Beach, CA, vol. Marie Curie Initial Training Network "SpineFX"}, language = {en} } @inproceedings{HornerDendorferKiisetal., author = {Horner, Marc and Dendorfer, Sebastian and Kiis, Arne and Lawrenchuk, Mike and Verma, Gunjan}, title = {A Patient based simulation workflow for orthopedic device design and analysis}, series = {SBC Ortho Workshop, June 2011}, booktitle = {SBC Ortho Workshop, June 2011}, language = {en} } @inproceedings{NonnKalwa, author = {Nonn, Aida and Kalwa, Christoph}, title = {The effect of microstructure, strain hardening and strain rate on the fracture behavior of high strength pipeline steels}, series = {2nd International Conference on Material Modelling (ICMM2), 31th August - 2nd September, 2011 at Mines Paris Tech, France}, booktitle = {2nd International Conference on Material Modelling (ICMM2), 31th August - 2nd September, 2011 at Mines Paris Tech, France}, language = {en} } @inproceedings{SchlechtSchulzKressner, author = {Schlecht, Berthold and Schulz, Carsten and Kressner, M.}, title = {Erstellung eines Grabwiderstandsmodells zur ganzheitlichen Simulation von Schaufelradantrieben}, series = {16. Fachtagung Sch{\"u}ttgutf{\"o}rdertechnik 2011 : Anlagen, Bauteile, Computersimulationen ; am 14. und 15. September in Magdeburg}, booktitle = {16. Fachtagung Sch{\"u}ttgutf{\"o}rdertechnik 2011 : Anlagen, Bauteile, Computersimulationen ; am 14. und 15. September in Magdeburg}, publisher = {LOGiSCH-Verlag}, isbn = {978-3-930385-77-5}, language = {de} } @inproceedings{SchlechtSchulz, author = {Schlecht, Berthold and Schulz, Carsten}, title = {Der modernisierte Schaufelradbagger - Ganzheitlicher Ansatz zur Leistungsoptimierung}, series = {DMK 2011 : Dresdner Maschinenelemente Kolloquium ; 29. und 30. November 2011 ; [Tagungsband]}, booktitle = {DMK 2011 : Dresdner Maschinenelemente Kolloquium ; 29. und 30. November 2011 ; [Tagungsband]}, publisher = {TUDpress}, address = {Dresden}, isbn = {978-3-942710-49-7}, language = {de} } @inproceedings{SchlechtSchulz, author = {Schlecht, Berthold and Schulz, Carsten}, title = {Ganzheitliche Simulation von Schaufelradantrieben unter Ber{\"u}cksichtigung der umgebenden Struktur}, series = {SIMPEP, Kongress f{\"u}r Simulation im Produktentstehungsprozess : 29. und 30. September 2011 in W{\"u}rzburg/Veitsh{\"o}chheim}, booktitle = {SIMPEP, Kongress f{\"u}r Simulation im Produktentstehungsprozess : 29. und 30. September 2011 in W{\"u}rzburg/Veitsh{\"o}chheim}, publisher = {FVA, Forschungsvereinigung Antriebstechnik}, address = {Frankfurt}, pages = {207 -- 232}, language = {de} } @inproceedings{WeberDendorferDullienetal., author = {Weber, Tim A. and Dendorfer, Sebastian and Dullien, Silvia and Grifka, Joachim and Verkerke, Gijsbertus Jacob and Renkawitz, Tobias}, title = {Measuring functional outcome after total hip replacement with subject-specific hip joint loading}, series = {Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine}, volume = {226}, booktitle = {Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine}, number = {12}, doi = {10.1177/0954411912447728}, pages = {939 -- 946}, abstract = {Total hip replacement is an often-performed orthopedic surgical procedure; the amount of procedures undertaken will increase since our life expectancy is growing. In order to optimize function, hip biomechanics should be restored to as near normal as possible. The goal of this pilot study was to determine whether or not it is feasible to compute the vectorial hip reaction force pathways on the head of the prosthesis and the force angles relative to the cup of the prosthesis that occur during gait in total hip replacement patients, serving as an objective measurement of the functional outcome following hip replacement. A three-dimensional gait analysis, measuring ground reaction forces and kinematics, was performed. The data retrieved from the gait analysis was used as the input for the musculoskeletal model to compute vectorial joint reaction forces for data processing. To evaluate the position and orientation of the joint reaction forces, the force path, as well as the force angles for the operated and non-operated joint, has been calculated during the stance phase of the specific leg. The force path for subject 2 on the non-operated side is only located in the posterior-lateral quarter, as is the force path for subject 1. In contrast to this subject, the force path for subject 2 at the operated hip joint can be found only within the anterior quarter of the head of the implant, where it is nearly equally distributed in the medio-lateral half of the prosthesis head. The force-inclination angles on the cup of subject 1, with respect to the plane of the socket face, indicates that the force vector is mainly positioned in the same quadrant when compared with subject 2 (in a cup-fixed coordinate system). The force-anteversion angle behaves similarly to the force-inclination angle, even when the effects are not as pronounced. The proposed methods in this article are aiming to define two functional outcomes of total hip replacement that are related to wear and rim loading. It is accepted that wear is not only a function of time, but a function of use. Owing to the methods listed in this article, we are able to determine a) the applied force and b) the sliding distance (force pathway) in a subject-specific manner. The computed hip-reaction force angles and the distance to the rim cup are a measurement for cup or rim loading, and occurs in the so-called safe-zones. This method may well give us insight into the biomechanical situation during gait, after receiving total hip replacement, that we need to fully understand the mechanisms acting on a hip joint and to prove a possible increase of functional outcome after receiving total hip replacement.}, subject = {H{\"u}ftgelenkprothese}, language = {en} } @inproceedings{MarkusRuettenKrenkelKessler, author = {Markus R{\"u}tten, and Krenkel, Lars and Kessler, Roland}, title = {Secondary Flow Effects as Physical Mechanism of Molecular Species Transport in Highly Oscillating Generic-Trachea Flows}, series = {83rd Annual Scientific Conference of the International Association of Applied Mathematics and Mechanics, 26.-30. M{\"a}rz 2012, Darmstadt, Germany}, booktitle = {83rd Annual Scientific Conference of the International Association of Applied Mathematics and Mechanics, 26.-30. M{\"a}rz 2012, Darmstadt, Germany}, abstract = {The high frequency oscillation artificial respiration technique is often the last hope for patients to survive highly damaged lung tissue. The mortality can significantly be reduced. In comparison to conventional artificial respiration the applied volume flow rate and pressure is significantly lowered in order to avoid further damaging of lung tissue and remaining intact alveolae. However, the physical mechanism of transport of oxygen to the aeriols under high frequency oscillation is not well understood. In the upper part of the lung convection is dominant, in contrast, the gas exchange in the lower parts of the lung is mainly driven by diffusion. It is not clear how associated gradients of concentrations of different molecular species are then achieved. Highly oscillating fluid flows has been a long research topic in fluid dynamics. It is known that oscillating pressure fluctuations are able to induce secondary flows, in particular, in curved ducts and pipes. The question is, whether the trachea enforces the generation of secondary flow by its kidney like cross section geometry. The influence of molecular species of different densities onto the formation of secondary flows and the convectional transport within the trachea is investigated. In order to clarify the physical mechanisms behind flow simulations have been conducted by using state of the art CFD techniques.}, language = {en} } @inproceedings{WeberStezowskiDullienetal., author = {Weber, Tim and Stezowski, P. and Dullien, Silvia and Dendorfer, Sebastian}, title = {Eine biomechanische Bewertung verschiedener Belastungsszenarios nach der Implantierung einer H{\"u}ft-Totalendoprothese}, series = {89. Jahrestagung der Vereinigung der Bayerischen Chirurgen e.V., 25. - 27. Juli 2012, Regensburg}, booktitle = {89. Jahrestagung der Vereinigung der Bayerischen Chirurgen e.V., 25. - 27. Juli 2012, Regensburg}, language = {de} } @inproceedings{WeberDullienPutzeretal., author = {Weber, Tim and Dullien, Silvia and Putzer, Michael and Dendorfer, Sebastian and Renkawitz, Tobias}, title = {Biomechanical outcome after computer-assisted vs. conventional THR - study concept and preliminary gait analysis results}, series = {GAMMA Workshop, Hannover, 2012}, booktitle = {GAMMA Workshop, Hannover, 2012}, language = {en} } @inproceedings{WeberStezowskiDullienetal., author = {Weber, Tim and Stezowski, P. and Dullien, Silvia and Putzer, Michael and Dendorfer, Sebastian}, title = {Eine biomechanische Bewertung verschiedener Belastungsszenarien nach Implantierung einer H{\"u}ft-Totalendoprothese}, series = {GAMMA Workshop, Hannover, 2012}, booktitle = {GAMMA Workshop, Hannover, 2012}, language = {de} } @inproceedings{SpreiterGalibarovDendorferetal., author = {Spreiter, G. and Galibarov, Pavel E. and Dendorfer, Sebastian and Ferguson, Stephen J.}, title = {Influence of kyphosis on spinal loading}, series = {10th International Symposium Computer Methods in Biomechanics and Biomedical Engineering (CMBBE) Meeting, 11. - 14. April 2012, Berlin}, booktitle = {10th International Symposium Computer Methods in Biomechanics and Biomedical Engineering (CMBBE) Meeting, 11. - 14. April 2012, Berlin}, language = {en} } @inproceedings{SchmailzlAmannGlockneretal., author = {Schmailzl, Anton and Amann, Thomas and Glockner, Markus and Fandanelli, Martin and Wagner, Marcus and Hierl, Stefan}, title = {Finite element analysis of thermoplastic probes under tensile load using ls-dyna compared to ansys workbench 14 in correlation to experimental investigations}, series = {ANSYS Conference \& 30th CADFEM Users' Meeting - ACUM, 24.-26- Oktober 2012, Kassel}, booktitle = {ANSYS Conference \& 30th CADFEM Users' Meeting - ACUM, 24.-26- Oktober 2012, Kassel}, editor = {CADFEM GmbH, and ANSYS Germany GmbH,}, address = {Grafing bei M{\"u}nchen}, pages = {1 -- 10}, abstract = {Joining thermoplastic requisitions is a popular technique to build sophisticated plastic applications. Therefore the laser-transmission welding process is used to join thermoplastic polymers in visible regions. The clamping force in this case plays a decisive role when it comes to the weld quality. Simulating the clamping pressure with finite element techniques is therefore highly attractive to understand the principal of the process. Thermoplastic polymers under tensile load often show a brittle behavior coupled with softening. Simulating such materials is quite difficult for FEM programs. In this case a finite element study of the tensile test in LS-DYNA and ANSYS Wb 14 with respect to the material models was analysed. The experimental data get validated in comparison with the FEM solution for a tensile test. The material models and the problems in simulating softening behavior for thermoplastic polymers were discussed}, language = {en} } @inproceedings{NonnKalwa, author = {Nonn, Aida and Kalwa, Christoph}, title = {Simulation of ductile crack propagation in high-strength pipeline steel using damage models}, series = {9th International Pipeline Conference 2012 (IPC 2012), Calgary, Canada}, booktitle = {9th International Pipeline Conference 2012 (IPC 2012), Calgary, Canada}, doi = {10.1115/IPC2012-90653}, pages = {7}, abstract = {The performance of engineering design of high-strength steel pipelines has revealed the necessity to revise current design procedures. Therefore, an improved and detailed comprehension of fracture mechanisms and development of failure prediction tools are required in order to derive new design criteria. In last decades the most successful failure prediction tools for steel structures subjected to various type of loading can be encountered in the field of damage mechanics. This paper aims to describe ductile fracture behavior of high-strength steel pipelines by applying three different damage models, Gurson-Tvergaard-Needelman (GTN), Fracture Locus Curve (FLC) and Cohesive Zone (CZ). These models are evaluated regarding their capability to estimate ductile crack propagation in laboratory specimens and linepipe components without adjusting the calibrated parameters. It can be shown that appropriate parameter sets can be identified to reproduce load-deformation and fracture resistance curves accurately. The strain rate effect on the fracture behavior is examined by dynamic tests on the BDWT specimens. Finally, the shortcomings of the applied models are pointed out with the reference to possible extensions and modifications.}, language = {en} } @inproceedings{SchmidJungbauerRomanoetal., author = {Schmid, Vinzent and Jungbauer, Bastian and Romano, Marco and Ehrlich, Ingo and Gebbeken, Norbert}, title = {The influence of different types of fabrics on the fibre volume content and porosity in basalt fibre reinforced plastics}, series = {2nd Applied Research Conference 2012 - ARC 25./26. June 2012}, booktitle = {2nd Applied Research Conference 2012 - ARC 25./26. June 2012}, editor = {Mottok, J{\"u}rgen and Ziemann, Olaf}, publisher = {Shaker}, pages = {162 -- 165}, abstract = {High quality semi-finished products with reproducible properties of basaltic fibres are hardly available on the market. In order to examine the properties of basalt fibre reinforced plastics high quality specimens are necessary. The fibre volume content and the porosity of the produced specimen are used as the typical criteria to evaluate the achieved quality of the produced material. The effect of the geometrical properties of the different semi-finished products on the fibre volume contents is relatively small whereas the porosity content is considerably affected.}, language = {en} } @inproceedings{SchmidJungbauerRomanoetal., author = {Schmid, Vinzent and Jungbauer, Bastian and Romano, Marco and Ehrlich, Ingo and Gebbeken, Norbert}, title = {Diminution of mass of different types of fibre reinforcements due to thermal load}, series = {Applied Research Conference 2012 - ARC 2012, 25./26. June 2012}, booktitle = {Applied Research Conference 2012 - ARC 2012, 25./26. June 2012}, editor = {Mottok, J{\"u}rgen and Ziemann, Olaf}, publisher = {Shaker}, pages = {231 -- 235}, language = {en} } @inproceedings{SchlechtMtauwegSchulz, author = {Schlecht, Berthold and Mtauweg, S and Schulz, Carsten}, title = {Dynamische Untersuchung des Azimutsystems und der Windrichtungsnachf{\"u}hrungsstrategie einer Windenergieanlage}, series = {3. VDI-Fachtagung Schwingungen von Windenergieanlagen 2012 mit Fachausstellung : Bremen, 07. und 08. Februar 2012}, booktitle = {3. VDI-Fachtagung Schwingungen von Windenergieanlagen 2012 mit Fachausstellung : Bremen, 07. und 08. Februar 2012}, publisher = {VDI-Verl.}, address = {D{\"u}sseldorf}, isbn = {978-3-18-092168-6}, language = {de} } @inproceedings{OttawaRomanoEhrlichetal., author = {Ottawa, Patrycja and Romano, Marco and Ehrlich, Ingo and Wagner, Marcus and Gebbeken, Norbert}, title = {The influence of ondulation in fabric reinforced composites on dynamic properties in a mesoscopic scale}, series = {11. LS-DYNA Forum, 9. - 10. Oktober 2012, Ulm}, booktitle = {11. LS-DYNA Forum, 9. - 10. Oktober 2012, Ulm}, pages = {171 -- 172}, abstract = {Structural mechanic properties of fiber reinforced plastics depend on the single components' properties, namely matrix and fiber [5]. Simple micromechanic homogenization theories reach a limit when a laminate consists of fabric reinforced layers instead of unidirectional layers. The ondulations of warp and fill yarn caused by the textile semi-finished product are the reason why the mesoscopic scale, which is in between the microscopic and the macroscopic scale, has to be taken into account when mechanically characterizing fabric reinforced composites [3]. In this scale a mesomechanic kinematic can be derived analytically. Especially, when considering free damped vibrations of structures the repeated acting of the kinematic correlation significantly affects the damping behaviour to higher values compared to theoretically predicted damping ratios. The model is investigated using Finite-Element-Analyses and basically validated experimentally.}, language = {en} } @inproceedings{NonnKalwa, author = {Nonn, Aida and Kalwa, Christoph}, title = {Failure modeling of pipeline X100 Material in temperature transition region}, series = {22nd International Society of Offshore and Polar Engineering 2012 (ISOPE 2012), Rhodes, Greece}, booktitle = {22nd International Society of Offshore and Polar Engineering 2012 (ISOPE 2012), Rhodes, Greece}, abstract = {This paper focuses on the characterization of the fracture performance of X100 material in transition temperature region using both experimental and numerical methods. The ductile fracture has been analyzed using tests on round notched bar specimens and standard fracture mechanics tests performed at room temperature. In previous publications the damage model Gurson-Tvergaard-Needleman (GTN) has been applied and verified by existing experimental data to describe ductile fracture behavior. The brittle fracture and the fracture in temperature transition region have been studied by means of deep and shallow notched SENB specimens at two different temperatures T=- 80°C and -40°C. Besides elastic-plastic analyses to quantify constraint levels for different initial crack configurations at the onset of cleavage fracture, the brittle failure has been described using modified Beremin model. The influence of the stable crack growth on the cleavage failure probability in temperature transition region has been captured by coupling the ductile fracture model (GTN) with the modified Beremin model. Finally, examples have been presented for the practical application of the numerical results on the fracture assessment of the flawed high-strength pipelines.}, language = {en} } @inproceedings{KofianiNonnWierzbickietal., author = {Kofiani, Kirki and Nonn, Aida and Wierzbicki, Tomasz and Kalwa, Christoph and Walters, Carey}, title = {Experiments and fracture modeling of high-strength pipelines for high and low stress triaxiality}, series = {22nd International Society of Offshore and Polar Engineering 2012 (ISOPE 2012), Rhodes, Greece, June 2012}, booktitle = {22nd International Society of Offshore and Polar Engineering 2012 (ISOPE 2012), Rhodes, Greece, June 2012}, abstract = {This paper provides results from a comprehensive study on mechanical characterization of high-strength pipeline steel, grade X100 using experimental and numerical methods. The material was characterized for anisotropic plasticity, fracture initiation for various states of stress, (pre-cracked) fracture toughness and uncracked ductility. The experimental program included tests on flat butterfly-shaped, central hole, notched and circular disk specimens for low stress triaxiality levels; as well as tests on round notched bar specimens and SENT fracture mechanics tests, for high values of stress triaxiality. This program covered a wide range of stress conditions and demonstrated its effect on the material resistance. Parallel to the experimental study, detailed numerical investigations were carried out to simulate all different experimental tests. Using an inverse method, a 3-parameter calibration was performed on the Modified Mohr-Coulomb (MMC) fracture model. Subsequently, the predictive capabilities of the MMC were evaluated by the comparison to the fracture toughness tests results, used extensively in the pipeline industry. The capabilities of the MIT fracture model have been demonstrated on an example of high strength offshore steel, X100. The outcome of this study was not only to provide, the overall characterization of the fracture behavior of this material as an example, but also to present the methodology on how to use the MMC model as a practical tool in pipeline design.}, language = {en} } @inproceedings{SchlechtSchulz, author = {Schlecht, Berthold and Schulz, Carsten}, title = {Erstellung eines modularen Mehrk{\"o}rpermodells zur Abbildung des dynamischen Verhaltens von Schaufelradbaggern}, series = {5. Fachtagung Baumaschinentechnik 2012 : Energie, Mechatronik, Simulation ; [20.-21. September 2012, Dresden] ; Tagungsband}, booktitle = {5. Fachtagung Baumaschinentechnik 2012 : Energie, Mechatronik, Simulation ; [20.-21. September 2012, Dresden] ; Tagungsband}, publisher = {FVB}, address = {Frankfurt am Main}, language = {de} } @inproceedings{SchlechtSchulzFranze, author = {Schlecht, Berthold and Schulz, Carsten and Franze, J.}, title = {Systemanalyse von Tagebaugroßger{\"a}ten durch modulare Abbildung in MKS-Modellen}, series = {AKIDA, 9. Aachener Kolloquium f{\"u}r Instandhaltung, Diagnose und Anlagen{\"u}berwachung, 14./15. November 2012, Aachen}, booktitle = {AKIDA, 9. Aachener Kolloquium f{\"u}r Instandhaltung, Diagnose und Anlagen{\"u}berwachung, 14./15. November 2012, Aachen}, language = {de} } @inproceedings{LaumerKargSchmidt, author = {Laumer, Tobias and Karg, Michael Cornelius Hermann and Schmidt, Michael}, title = {Neue Prozessstrategien zur Herstellung von Multi- Material-Bauteilen und Gradientenwerkstoffen}, series = {Zukunft individuell gestalten : Industriekolloquium des Sonderforschungsbereichs 814 - Additive Fertigung ; [Dezember 2012 ; N{\"u}rnberg]}, booktitle = {Zukunft individuell gestalten : Industriekolloquium des Sonderforschungsbereichs 814 - Additive Fertigung ; [Dezember 2012 ; N{\"u}rnberg]}, address = {Erlangen}, pages = {101 -- 116}, abstract = {Das additive Fertigungsverfahren, dem gemeinhin die gr{\"o}ßten Potentiale zugesprochen werden, ist das Laserstrahlschmelzen im Pulverbett von Kunststoffen (LSS-K) und von Metallen (LSS-M). Wie bei anderen Techniken der additiven Fertigung werden Bauteile direkt aus CAD-Dateien ohne zus{\"a}tzliche Werkzeuge bei enormer konstruktiver Freiheit gefertigt. Die resultierenden Werkstoffeigenschaften sind vergleichbar mit konventionelleren Prozessrouten wie etwa dem Spritzgießen thermoplastischer Polymere beziehungsweise auf der Seite der Metalle dem Schmieden oder Gießen. Derzeit wird der Einsatz des LSS zur Fertigung von Endprodukten in kleinen St{\"u}ckzahlen erschwert von nicht ausreichender Prozessstabilit{\"a}t und, insbesondere bei Kunststoffen, von der eingeschr{\"a}nkten Werkstoffauswahl. Bisher werden f{\"u}r beide Werkstoffklassen Bauteile aus jeweils einem einzigen Ausgangsmaterial hergestellt. N{\"a}herungsweise erzeugt LSS also einheitliche Materialeigenschaften {\"u}ber das gesamte Bauteil hinweg. Ein Ansatz, der in den Teilprojekten A5 und B6 des Sonderforschungsbereichs 814 verfolgt wird, ist die Realisierung von Multi-Material-Bauteilen mittels LSS-K beziehungsweise LSS-M.}, language = {de} } @inproceedings{LaumerAppelSticheletal., author = {Laumer, Tobias and Appel, Peter and Stichel, Thomas and Amend, Philipp}, title = {Untersuchungen zum Absorptionsverhalten von Pulversch{\"u}ttungen f{\"u}r das Laserstrahlschmelzen von Kunststoffen Conference}, series = {Rapid.Tech, 2013, Erfurt}, booktitle = {Rapid.Tech, 2013, Erfurt}, abstract = {Die Energieeinbringung in Form von elektromagnetischer Strahlung in das Pulverbett beim selektiven Laserstrahlschmelzprozess von Kunststoffen wird maßgeblich durch das Absorptionsverhalten der Pulverwerkstoffe bestimmt. Aufgrund von Vielfachreflexionen an den einzelnen Pulverpartikeln in den Poren weisen Pulverwerkstoffe im Vergleich zu makroskopischen Festk{\"o}rpern andere Absorptionseigenschaften auf. Im vorliegenden Beitrag wird daher ein geeigneter Messaufbau zur Bestimmung der optischen Materialeigenschaften von verschiedenen Pulverwerkstoffen vorgestellt. Mittels eines Ulbricht-Kugel-Messaufbaus wird der Reflexions-, der Transmissions- und der Absorptionsgrad von pulverf{\"o}rmigen Werkstoffen bei einer Wellenl{\"a}nge von 10,6 µm eines CO2-Lasers und unterschiedlichen Schichtst{\"a}rken ermittelt. Neben den Werkstoffen Polyamid 12 und Polyethylen im reinen Zustand werden Mischungen mit Additiven, wie beispielsweise Graphit, analysiert und verglichen. Durch die Beimischungen kann eine f{\"u}r den Schmelzprozess zu geringe Absorption des reinen Kunststoffes wie im Fall von Polyethylen-Pulver bei einer Wellenl{\"a}nge von 10,6 µm gezielt erh{\"o}ht werden, wodurch die Entwicklung neuer Pulverwerkstoffe erleichtert wird.}, language = {de} } @inproceedings{FriedrichFeldmannKrenkeletal., author = {Friedrich, Janet and Feldmann, Daniel and Krenkel, Lars and Wagner, Claus and Schreiber, Laura Maria}, title = {19F Gas Flow Measurement of C3F7H During Constant Flow and High Frequency Oscillatory Ventilation}, series = {Discovery, innovation \& application - advancing mr for improved health : ISMRM 21st Annual Meeting \& Exhibition ; SMRT 22nd Annual Meeting Salt Lake City, Utah, USA 20-26 April 2013}, volume = {21}, booktitle = {Discovery, innovation \& application - advancing mr for improved health : ISMRM 21st Annual Meeting \& Exhibition ; SMRT 22nd Annual Meeting Salt Lake City, Utah, USA 20-26 April 2013}, organization = {International Society for Magnetic Resonance in Medicine}, abstract = {The aim of the current study is the development of MRI methods that enable the investigation of gas flow mechanisms during high frequency oscillatory ventilation. This work includes flow measurements during three constant flows (19.9, 30.6 and 41.4 L min-1) and the comparison to direct numerical simulations (DNS) using a second-order-acurate finite-volume method and to data measured with a volume flow meter. 19F-MRI, DNS and flow meter data are in good agreement. Flow measurements during HFOV of 4 Hz were successfully performed and velocity profiles could be recorded at different phases of the ventilation cycle.}, language = {en} } @inproceedings{PutzerGalibarovDendorfer, author = {Putzer, Michael and Galibarov, Pavel E. and Dendorfer, Sebastian}, title = {Influence of vertebral parameters on lumbar spine loading}, series = {Pre-meeting SpineFX, Eurospine 2013, Liverpool, UK}, booktitle = {Pre-meeting SpineFX, Eurospine 2013, Liverpool, UK}, language = {en} } @inproceedings{DendorferPenzkofer, author = {Dendorfer, Sebastian and Penzkofer, Rainer}, title = {Experimentelle Untersuchung der Belastungen im Kopf beim Treten}, series = {Fachsymposium "Treten gegen den Kopf", April 2013, N{\"u}rnberg}, booktitle = {Fachsymposium "Treten gegen den Kopf", April 2013, N{\"u}rnberg}, language = {de} } @inproceedings{Dendorfer, author = {Dendorfer, Sebastian}, title = {Einf{\"u}hrung in die Mechanik}, series = {Biomechanik Workshop, Klinikum Bad Abbach, Nov. 2013}, booktitle = {Biomechanik Workshop, Klinikum Bad Abbach, Nov. 2013}, language = {de} } @inproceedings{Dendorfer, author = {Dendorfer, Sebastian}, title = {Innovationen in der Medizintechnik}, series = {Oberpfalztag Weiherhammer, Nov. 2013}, booktitle = {Oberpfalztag Weiherhammer, Nov. 2013}, language = {de} } @inproceedings{SchmailzlHierl, author = {Schmailzl, Anton and Hierl, Stefan}, title = {Thermo-mechanische Struktursimulation mit ANSYS Workbench 14.0 am Beispiel des Laser-Durchstrahlschweißens}, series = {ANSYS Conference \& 31st CADFEM Users' Meeting - ACUM, June 19-21, Mannheim}, booktitle = {ANSYS Conference \& 31st CADFEM Users' Meeting - ACUM, June 19-21, Mannheim}, editor = {CADFEM GmbH, and ANSYS Germany GmbH,}, address = {Grafing bei M{\"u}nchen, Darmstadt}, pages = {1 -- 16}, language = {de} } @inproceedings{SchmailzlHierl, author = {Schmailzl, Anton and Hierl, Stefan}, title = {Online-process monitoring of laser transmission welding for polymers}, series = {Applied Research Conference 2013, ARC 2013 ; 17th and 18th October 2013, Deggendorf}, booktitle = {Applied Research Conference 2013, ARC 2013 ; 17th and 18th October 2013, Deggendorf}, editor = {Ziemann, Olaf and Bogner, Werner and Mottok, J{\"u}rgen}, publisher = {Shaker}, address = {Aachen}, pages = {374 -- 378}, language = {en} } @inproceedings{VoellingNonnSchneider, author = {V{\"o}lling, Alexander and Nonn, Aida and Schneider, Ingo}, title = {Anwendung des Koh{\"a}sivzonenmodells zur Abbildung von duktilem dynamischen Rissfortschritt in Gasfernleitungen}, series = {45. Tagung des AK Bruch, Berlin, Germany}, booktitle = {45. Tagung des AK Bruch, Berlin, Germany}, pages = {253 -- 262}, subject = {Ferngasleitung}, language = {de} } @inproceedings{NonnCerroneStallybrassetal., author = {Nonn, Aida and Cerrone, Albert R. and Stallybrass, C. and Meuser, H.}, title = {Microstructure-based modeling of high-strength linepipe steels}, series = {6th Pipeline Technology Conference 2013, 6-9 October, Ostend, Belgium}, booktitle = {6th Pipeline Technology Conference 2013, 6-9 October, Ostend, Belgium}, doi = {10.13140/2.1.2797.4404}, abstract = {HE MODERN LONGITUDINALLY WELDED pipes with new generation of steel materials exhibit excellent mechanical properties due to the continuous improvements in thermomechanical controlled processing of plates (TMCP) and pipe (UOE) production processes. While the adjustment of process parameters allows for optimized design of microstructure, safe installation and operation of these pipes for long distance, gas transmission pipelines require a detailed knowledge and characterization of their deformation and fracture performance for specific application. Although the influence of texture on the material properties can be qualitatively estimated, a quantitative link between the microstructural constituents and mechanical behavior is still missing. This paper aims to present the procedure for the development of microstructure-based model to quantitatively describe the mechanical behavior of bainitic X80 pipeline steel. In the first step, the metallographic analysis is conducted to identify the microstructural characteristics, such as volume fractions of microstructure constituents (granular and lower bainite, M-A phase) and their distributions. The strength properties in terms of flow curves are determined by tensile tests on mini-flat and round bar specimens with different sizes. Subsequently, a 2D three-phase model is developed based on the results from the quantitative analyses of microstructure with each phase modeled using the von-Mises plasticity theory. The flow curves of single phases are estimated by considering experimental findings, the chemical composition and microstructural description of each phase. This 2D FE model is then applied to predict ielding and hardening behavior. In addition to the 2D three-phase model, a 3D two-phase model is developed for the purposes of exploring the viability of using a spectral solver to analyze X80 synthetic microstructures. Here, the FFT-based approach is compared against the crystal-plastic finite-element method. The results contribute to a better understanding of the mechanical behavior and allow a more precise microstructure design of the bainitic steels.}, language = {en} } @inproceedings{NonnKalwa, author = {Nonn, Aida and Kalwa, Christoph}, title = {Analysis of dynamic ductile fracture propagation in pipeline steels}, series = {6th Pipeline Technology Conference (2013), Ostend, Belgium}, booktitle = {6th Pipeline Technology Conference (2013), Ostend, Belgium}, doi = {10.13140/2.1.4370.3046}, abstract = {Analysis of dynamic ductile fracture propagation in pipeline steels: a damage-T IS A WELL-ESTABLISHED fact that the successful application of new generation of high-strength steel grades for long-distance gas transmission depends strongly on full understanding and appropriate characterization of fracture resistance. A damage mechanics approach has found to be a very promising tool in supporting the experimental characterization of ductile fracture propagation. The major advantage of this approach lies in the consideration of the influence of local stress and strain variables on the damage evolution and thus its capability to describe the fracture resistance of the pipelines with different stress triaxiality level by using the same set of parameters. However, the wider application of this approach has been limited due to the issues such as reliable determination of input parameters and required material properties, mesh size dependence, etc.. The objective of this paper is to characterize dynamic ductile fracture resistance of X65 and X80 pipeline materials and to demonstrate the potential of damage mechanics approach for the simulation of dynamic fracture propagation by using two damage models: (1) Cohesive Zone (CZ) model and (2) Gurson-Tvergaard-Needleman (GTN) model. In the first step, results from quasi-static and dynamic tensile tests are used to describe plasticity in terms of flow curves. The calibration of input parameters for both models is performed by using the load-deformation curves from quasi-static tests on non-standard drop-weight tear (DWT) specimens with pre-fatigued crack. b. In the next step, estimated damage model parameters are verified by means of the dynamic tests on the pressed and Chevron notch DWT specimens. Different amounts of crack growth are established by varying the drop height. The experimental fracture resistance is quantified in terms of J-integral at specific crack length. The numerical results are evaluated with respect to global load-deformation and fracture resistance behavior. Furthermore, damage simulations are applied for quantification of local stress conditions in order to identify the major factors controlling the crack propagation. The results reported here serve as a basis for better understanding of fracture performance in dependences of geometry and material properties.}, language = {en} } @inproceedings{NonnKalwa, author = {Nonn, Aida and Kalwa, Christoph}, title = {Application of probabilistic fracture mechanics for safety assessment of longitudinally welded linepipes}, series = {6th Pipeline Technology Conference (2013), Ostend, Belgium}, booktitle = {6th Pipeline Technology Conference (2013), Ostend, Belgium}, language = {en} } @inproceedings{NonnKalwa, author = {Nonn, Aida and Kalwa, Christoph}, title = {Application of damage mechanics approach for crack propagation in pipeline}, series = {19th Biennial Joint Technical Meeting (JTM) on Pipeline Research, April 29 - May 3, 2013, Sydney, Australia}, booktitle = {19th Biennial Joint Technical Meeting (JTM) on Pipeline Research, April 29 - May 3, 2013, Sydney, Australia}, language = {en} } @inproceedings{NonnWesselSchmidt, author = {Nonn, Aida and Wessel, Waldemar and Schmidt, Tanja}, title = {Application of finite element analysis for assessment of fracture behavior of modern high toughness seamless pipeline steels}, series = {23rd International Society of Offshore and Polar Engineering 2013 (ISOPE 2013), Anchorage, USA}, booktitle = {23rd International Society of Offshore and Polar Engineering 2013 (ISOPE 2013), Anchorage, USA}, doi = {10.13140/2.1.4239.2322}, abstract = {Fracture behavior of seamless pipeline material X65Q acc. to API 5L has been studied both experimentally and numerically at different loading conditions (quasi-static vs. dynamic) and temperatures. The recent findings have shown difficulties in applying well established methods for determination of transition behavior or prediction of ductile crack arrest for the new generation of high-toughness steels. The irregular fracture performance (e.g. so-called "abnormal inverse fracture" appearance, significant scattering in ductile-to-brittle-transition-temperature region, etc.) suggests that the influence of pipe dimensions, loading parameters, crack initiation resistance as well as testing procedure on the fracture behavior has been neither understood nor properly described. This work aims to shed light on these questions regarding the applicability of conventional methods and to better illuminate most relevant parameters affecting fracture behavior of high toughness steels. To achieve this goal, experimental data basis for analysis of fracture behavior in transition and upper shelf regime has been established by conducting quasi-static fracture mechanics tests and dynamic tests on Battelle Drop Weight Tear (BDWT or DWT) specimens at different temperatures. The evaluation of obtained test results in upper shelf has been additionally complemented by numerical simulation of damage behavior. The results highlight the influence of stress conditions on fracture behavior with reference to pipe dimensions and loading conditions and, subsequently, may be used as a basis for revision of existing design methods.}, subject = {Rissfortschritt}, language = {en} } @inproceedings{ValentinoRomanoEhrlichetal., author = {Valentino, Piergiorgio and Romano, Marco and Ehrlich, Ingo and Furgiuele, Franco and Gebbeken, Norbert}, title = {Mechanical characterization of basalt fibre reinforced plastic with different fabric reinforcements - Tensile tests and FE-calculations with representative volume elements (RVEs)}, series = {Acta Fracturae - XXll Convegno Nazionale IGF (Italiano Gruppo Frattura)}, booktitle = {Acta Fracturae - XXll Convegno Nazionale IGF (Italiano Gruppo Frattura)}, editor = {Iacovello, F. and Risitano, G. and Susmel, L.}, abstract = {This paper describes the results of tensile tests and finite element (FE) calculations with representative volume elements (RVEs) of basalt fibre reinforced plastic with two different types of fabric reinforcements. As fabric reinforcements show repeating ondulations of warp and fill yarn, simple mixtures laws reach their limits. That is the reason why the mesoscopic dimension, lying between the microscopic and the macroscopic dimension, has to be taken into account when a mechanical characterization of fabric reinforced composites is carried out. The aim of this work is to determine the stiffness of a fabric reinforced composite in warp and fill direction with numerical investigations. The simulations are based on FE-calculation with two different RVEs. The tensile tests and the FE-calculations have been carried out for two different types of basalt fabrics, namely twill 2/2 and twill 1/3. The comparison between the experimental data and the results of the FE-calculations are provided in order to support the validity of the proposed model.}, language = {en} } @inproceedings{SchlechtSchulz, author = {Schlecht, Berthold and Schulz, Carsten}, title = {Ganzheitliche Lastbetrachtung von Antriebssystemen mithilfe komplexer Mehrk{\"o}rpermodelle}, series = {8. VDI Fachtagung. Schwingungen in Antrieben, 05. und 06. November 2013, Fulda}, booktitle = {8. VDI Fachtagung. Schwingungen in Antrieben, 05. und 06. November 2013, Fulda}, language = {de} } @inproceedings{SchlechtSchulz, author = {Schlecht, Berthold and Schulz, Carsten}, title = {Zum Einsatz modularer MKS-Modelle zur Systemanalyse von Tagebaugroßger{\"a}ten}, series = {Groß- und Sondergetriebe im Schwermaschinen- und Anlagenbau 2013, Essen}, booktitle = {Groß- und Sondergetriebe im Schwermaschinen- und Anlagenbau 2013, Essen}, language = {de} } @inproceedings{SchlechtSchulz, author = {Schlecht, Berthold and Schulz, Carsten}, title = {Aktive Schwingungsd{\"a}mpfung in drehzahlgeregelten mechatronischen Antriebssystemen}, series = {DMK - Dresdner Maschinenelemente Kolloquium, 2013, Dresden}, booktitle = {DMK - Dresdner Maschinenelemente Kolloquium, 2013, Dresden}, language = {de} } @inproceedings{SchulzeSchulzRosenloecher, author = {Schulze, T. and Schulz, Carsten and Rosenl{\"o}cher, T.}, title = {Critical evaluation of long-time measurements and measurement-based simulation of selected operating conditions}, series = {COWEC 2013, 18. und 19. Juni 2013, Berlin}, booktitle = {COWEC 2013, 18. und 19. Juni 2013, Berlin}, language = {en} } @inproceedings{SchlechtSchulz, author = {Schlecht, Berthold and Schulz, Carsten}, title = {Modellbildung und Simulation eines Tagebaugroßger{\"a}tes}, series = {ATK 2013 - 15. Antriebstechnisches Kolloquium - 19.-20. M{\"a}rz 2013}, booktitle = {ATK 2013 - 15. Antriebstechnisches Kolloquium - 19.-20. M{\"a}rz 2013}, editor = {Neubert, Sebastian and Jacobs, Georg}, publisher = {RWTH Universit{\"a}t Aachen}, language = {de} } @inproceedings{LaumerKargSchmidt, author = {Laumer, Tobias and Karg, Michael Cornelius Hermann and Schmidt, Michael}, title = {Additive Manufacturing of Gradient and Multimaterial Components}, series = {International Conference on Competitive Manufacturing COMA, 2013, Stellenbosch}, booktitle = {International Conference on Competitive Manufacturing COMA, 2013, Stellenbosch}, abstract = {In the paper first results regarding the realisation of gradient and multi-material parts manufactured by Laser Beam Melting in powder bed of metals and polymers are published. Gradient properties of additively manufactured metal parts can be achieved by varying the composition of alloying components in the powder and adapting process strategies. As an alternative to atomizing pre-alloyed materials, mixtures of different powders are investigated. For realizing multi-material-parts from polymers, at first relevant material properties concerning compatibility have to be analysed. Therefore the paper shows the main requirements for compatibility between different materials and also first results regarding the compatibility of polymer powders and possible combinations for the manufacturing of multi-material components by laser beam melting of polymers.}, language = {en} } @inproceedings{LaumerKargSchmidt, author = {Laumer, Tobias and Karg, Michael Cornelius Hermann and Schmidt, Michael}, title = {Neue Prozessstrategien zur Herstellung von Multi-Material-Bauteilen mit Hilfe des Laserstrahlschmelzens}, series = {Industriekolloquium des SFB 814, 2, 2013, N{\"u}rnberg}, booktitle = {Industriekolloquium des SFB 814, 2, 2013, N{\"u}rnberg}, publisher = {Universit{\"a}t Erlangen-N{\"u}rnberg, Lehrstuhl f{\"u}r Kunststofftechnik}, isbn = {978-3-931864-59-0}, language = {de} } @inproceedings{LaumerStichelAmendetal., author = {Laumer, Tobias and Stichel, Thomas and Amend, Philipp and Schmidt, Michael and Gachot, A.}, title = {Simultaneous Energy Deposition for Laser Beam Melting of Polymers}, series = {Proceedings of the Polymer Processing Society 29th Annual Meeting, N{\"u}rnberg, 2013}, booktitle = {Proceedings of the Polymer Processing Society 29th Annual Meeting, N{\"u}rnberg, 2013}, publisher = {American Institute of Physics}, address = {New York}, language = {en} } @inproceedings{GalkaKlenkGuenthner, author = {Galka, Stefan and Klenk, Eva Marianne and G{\"u}nthner, Willibald A.}, title = {Planning of production supermarkets for production supply}, series = {Proceedings of 2013 IEEE International Conference on Service Operations and Logistics, and Informatics, 28-30 July 2013, Dongguan, China}, booktitle = {Proceedings of 2013 IEEE International Conference on Service Operations and Logistics, and Informatics, 28-30 July 2013, Dongguan, China}, publisher = {IEEE}, address = {Piscataway, NJ}, isbn = {978-1-4799-0530-0}, doi = {10.1109/SOLI.2013.6611458}, pages = {456 -- 461}, abstract = {Production supermarkets are a system to ensure high-frequency, demand-oriented, in-plant production supply with low lot sizes. The paper presents methods to design and dimension these systems using qualitative design criteria and quantitative approaches based on well-known analytical methods for conventional order picking systems. The methods help to design layout, provision type and path strategy and to derive space consumption and the number of supermarket employees required to fulfill a defined demand.}, language = {de} } @inproceedings{EisenriedRomanoJungbaueretal., author = {Eisenried, Michael and Romano, Marco and Jungbauer, Bastian and Ehrlich, Ingo and Gebbeken, Norbert}, title = {Influence of parameters of the production process on the material quality of unidirectionally reinforced prepregs}, series = {Applied Research Conference 2013, ARC 2013 ; 17th and 18th October 2013, Deggendorf}, booktitle = {Applied Research Conference 2013, ARC 2013 ; 17th and 18th October 2013, Deggendorf}, editor = {Ziemann, Olaf and Bogner, Werner and Mottok, J{\"u}rgen}, publisher = {Shaker}, address = {Aachen}, pages = {70 -- 75}, language = {en} } @inproceedings{LaumerKoopmannSticheletal., author = {Laumer, Tobias and Koopmann, Jonas and Stichel, Thomas and Amend, Philipp}, title = {Generation of multi-material parts with alternating material layers by Simultaneous Laser Beam Meltingof polymers}, series = {International Conference on Additive Technologies, 15 - 17 Oct 2014, Wien}, booktitle = {International Conference on Additive Technologies, 15 - 17 Oct 2014, Wien}, abstract = {By using Additive Manufacturing technologies, like Laser Beam Melting (LBM) of polymers, parts can be realized within single days and necessary modifications can be quickly adapted. With increasing complexity, products are often made out of different polymer materials and the need for multi-material parts is an increasing industry requirement, which cannot be fulfilled by the single material parts realizable by LBM. Therefore, Simultaneous Laser Beam Melting (SLBM) as a new Additive Manufacturing technology offers the possibility to build parts consisting of different polymer materials. The realizable parts combine different material properties, like differing stiffness or chemical resistances, within a single part. Up to now, different materials are deposited next to each other on the building platform, thus the boundary surface between the different polymers is orientated perpendicular to the building direction. For this paper, the polymer powders are alternated in building direction. Thus, the boundary surface is orientated horizontally and is larger, both influencing the boundary surface and resulting part properties, which are analyzed by a high-resolution thermal imaging system and by cross sections.}, language = {en} } @inproceedings{StichelAmendLaumeretal., author = {Stichel, Thomas and Amend, Philipp and Laumer, Tobias and Roth, Stephan}, title = {Electrostatic Multi-Material Powder Deposition for Simultaneous Laser Beam Melting}, series = {International Conference on Information, Communication and Automation Technologies (ICAT), 2014, Wien}, booktitle = {International Conference on Information, Communication and Automation Technologies (ICAT), 2014, Wien}, abstract = {In this paper, the use of electrostatic polymer powder transfer methods for the preparation of multi-material layers is discussed with respect to the application in Simultaneous Laser Beam Melting (SLBM). Therefore, the basic principles of the single process steps as well as the challenges in combination with SLBM are considered verifying the critical process steps. On that base, process concepts are developed which might enable the fabrication of high quality multi-material parts in the future. Moreover, since the polymer powders typically used with Laser Beam Melting differ strongly from common toners for e. g. electrophotographic printing, an experimental setup was built to study the powder transfer with an electrically chargeable transfer plate using polyamide 12 powder. The results of this study show that transfer of powders usable for Laser Beam Melting can be achieved, but depends on the electric field strength which is a function of the gap between transfer and substrate plate and the intermediate electric potential.}, language = {en} } @inproceedings{LaumerStichelAmendetal., author = {Laumer, Tobias and Stichel, Thomas and Amend, Philipp and Roth, Stephan and Schmidt, Michael}, title = {Analysis of Temperature Gradients during Simultaneous Laser Beam Melting of Polymers}, series = {Physics Procedia}, volume = {56}, booktitle = {Physics Procedia}, publisher = {Elsevier}, doi = {10.1016/j.phpro.2014.08.159}, pages = {167 -- 175}, abstract = {By simultaneous laser beam melting (SLBM), different polymer powders can be processed to multi-material parts, which offers the potential to enlarge the field of application for conventional LBM. In a SLBM process, a powder bed consisting of different polymers and therefore with different melting and crystallization temperatures is deposited. Besides the use of infrared emitters for preheating the lower melting polymer, a CO2 laser distributes the necessary preheating temperature of the higher melting polymer. In the last step, a thulium fibre laser distributes the energy necessary for melting the two preheated powders simultaneously. In order to analyze the temperature gradients of the process on the powder surface and in deeper layers, a high-resolution thermal imaging system and thermocouples are used.}, language = {en} } @inproceedings{HoecherlBottkeSchlegl, author = {H{\"o}cherl, Johannes and Bottke, Christian and Schlegl, Thomas}, title = {Eine redundante Steuerungsarchitektur zur Realisierung sicherer Mensch-Roboter-Kollaboration - Entwicklung gem{\"a}ß DIN EN ISO 10218, 13849 und 12100}, series = {Tagungsband AALE 2014}, booktitle = {Tagungsband AALE 2014}, publisher = {Deutscher Industrieverlag}, address = {M{\"u}nchen}, isbn = {978-3-8356-7142-3}, pages = {165 -- 173}, abstract = {Das Forschungsprojekt ManuCyte konzentriert sich auf die Realisierung einer Plattform f{\"u}r die Kultivierung menschlicher Zellen und Gewebe im industriellen Maßstab. F{\"u}r die Mensch-Roboter-Kolloboration ist die Robotersteuerung technologisch diversit{\"a}r und redundant ausgef{\"u}hrt. Skizziert und analysiert wird ein prototypisches Robotersystem zum Erhalt von sicherer Mensch-Roboter-Kollaboration. Eine normgerechte Risikobeurteilung wird anhand der vorliegenden Anwendung Schritt f{\"u}r Schritt aufgezeigt. Wichtige Kenngr{\"o}ßen zur Bestimmung des sicherheitstechnischen Leistungsgrades sicherheitsrelevanter Steuerungsfunktionen werden exemplarisch berechnet und zusammengefasst. Die Vorgehensweise der Steuerungsentwicklung und die entwickelte Steuerungsarchitektur werden aufgezeigt. Außerdem werden die Sicherheitsanforderungen exemplarisch validiert und die Ergebnisse diskutiert. Aufgezeigt werden die Entwicklungsschritte zu einer m{\"o}glichen Zertifizierung. A prototypic robot system for Human-Robot Collaboration is sketched and analyzed in the article at hand. For the present application, the risk assessment according to the relevant standards is visualized step by step. Important parameters to determine the safety performance level of safety related control functions are calculated and summarized. The procedure to develop a safe control system and the developed control architecture are shown. Furthermore, the safety requirements are validated exemplarily and the results are discussed. Possible steps to carry the system to a certification complete the present article.}, language = {de} } @inproceedings{LaumerStichelBocketal., author = {Laumer, Tobias and Stichel, Thomas and Bock, Thomas and Amend, Philipp and Schmidt, Michael}, title = {Characterization of temperature-dependent optical material properties of polymer powders}, series = {AIP Conference Proceedings}, booktitle = {AIP Conference Proceedings}, number = {1}, publisher = {AIP Publishing}, doi = {10.1063/1.4918508}, abstract = {In former works, the optical material properties of different polymer powders used for Laser Beam Melting (LBM) at room temperature have been analyzed. With a measurement setup using two integration spheres, it was shown that the optical material properties of polymer powders differ significantly due to multiple reflections within the powder compared to solid bodies of the same material. Additionally, the absorption behavior of the single particles shows an important influence on the overall optical material properties, especially the reflectance of the powder bed. Now the setup is modified to allow measurements at higher temperatures. Because crystalline areas of semi-crystalline thermoplastics are mainly responsible for the absorption of the laser radiation, the influence of the temperature increase on the overall optical material properties is analyzed. As material, conventional polyamide 12 and polypropylene as new polymer powder material, is used. By comparing results at room temperature and at higher temperatures towards the melting point, the temperature-dependent optical material properties and their influence on the beam-matter interaction during the process are discussed. It is shown that the phase transition during melting leads to significant changes of the optical material properties of the analyzed powders.}, language = {en} } @inproceedings{AlMunajjedNolteRasmussenetal., author = {Al-Munajjed, Amir Andreas and Nolte, Daniel and Rasmussen, John and Dendorfer, Sebastian}, title = {Force distribution in the foot during braking - a musculoskeletal approach}, series = {Human Modeling Symposium 2014, Munich, Germany}, booktitle = {Human Modeling Symposium 2014, Munich, Germany}, abstract = {High loads can appear in the individual joints of the human foot while the driver uses the pedals, in particular, during breaking. Measuring these internal forces is very difficult or almost impossible; therefore, advanced models are necessary to perform musculoskeletal simulations. The objective of this investigation was to see what loads are acting in the individual foot joints from the phalanges to calcaneus and talus during different brake scenarios. The Glasgow-Maastricht AnyBody Foot Model with 26 separate segments, connected by joints, ligaments and muscles was used inside the AnyBody Modeling System to compute individual mid foot joint loads. The amount, the direction of the force and additionally also the load insertion point was varied for several simulations. Figure 1: Seated musculoskeletal body model with applied brake force and forces for the lateral, intermediate and medial cuneiform-navicular joint for two different brake forces. The simulation showed that for the different brake scenarios, different muscles will be activated in the human and therefore different loads are apply in the fore-and mid-foot, respectively. The torso of the subject was assumed to be fixed in the seat. Further studies are ongoing to simulate the seat as an elastic element that allows different H-point locations according to the different loadings in the foot from the brake pedal using a new inverse dynamics analysis method called force-dependent kinematics.}, language = {en} } @inproceedings{WeberDendorferBulstraetal., author = {Weber, Tim and Dendorfer, Sebastian and Bulstra, Sjoerd K. and Verkerke, Gijsbertus Jacob and Renkawitz, Tobias}, title = {Biomechanical Outcome after computer-assisted vs. Conventional THR}, series = {ANSYS Conference \& 32th CADFEM Users' Meeting 2014, 04.-06. Juni, N{\"u}rnberg}, booktitle = {ANSYS Conference \& 32th CADFEM Users' Meeting 2014, 04.-06. Juni, N{\"u}rnberg}, language = {en} } @inproceedings{PutzerPenzkoferEhrlichetal., author = {Putzer, Michael and Penzkofer, Rainer and Ehrlich, Ingo and Rasmussen, John and Gebbeken, Norbert and Dendorfer, Sebastian}, title = {Musculoskeletal simulations to investigate the influence of vertebral geometrical parameters on lumbar spine loading}, series = {7th World Congress of Biomechanics, Boston, United States, 04/07/14 -11/07/14}, booktitle = {7th World Congress of Biomechanics, Boston, United States, 04/07/14 -11/07/14}, language = {de} } @inproceedings{StrieglKujatDendorfer, author = {Striegl, B. and Kujat, Richard and Dendorfer, Sebastian}, title = {Quantitative analysis of cartilage surface by confocal laser scanning microscopy}, series = {Biomedizinische Technik}, volume = {59}, booktitle = {Biomedizinische Technik}, number = {s1-A}, doi = {10.1515/bmt-2014-4012}, pages = {24}, language = {en} } @inproceedings{PreischlSchmailzlHierl, author = {Preischl, Antonius and Schmailzl, Anton and Hierl, Stefan}, title = {Experimental study to evaluate the process window for laser transmission welding of plastics}, series = {Applied Research Conference 2014 - ARC 2014, 5th July 2014, Ingolstadt}, booktitle = {Applied Research Conference 2014 - ARC 2014, 5th July 2014, Ingolstadt}, editor = {Ziemann, Olaf and Mottok, J{\"u}rgen and Pforr, Johannes}, publisher = {Shaker}, address = {Aachen}, pages = {517 -- 522}, language = {en} } @inproceedings{Hierl, author = {Hierl, Stefan}, title = {Laser Transmission Welding of Plastics}, series = {15th International Materials Symposium - IMSP'2014, Denizli, 2014}, booktitle = {15th International Materials Symposium - IMSP'2014, Denizli, 2014}, editor = {Meran, Cemal}, pages = {1084 -- 1093}, language = {en} } @inproceedings{RomanoMicklitzOlbrichetal., author = {Romano, Marco and Micklitz, Matthias and Olbrich, Florian and Bierl, Rudolf and Ehrlich, Ingo and Gebbeken, Norbert}, title = {Experimental investigation of damping properties of unidirectionally and fabric reinforces plastics by the free decay method}, series = {Proceeding of the 15th International Materials Symposium (IMSP´2014), Pamukkale University (Denizli, Turkey), 15./17. October 2014}, booktitle = {Proceeding of the 15th International Materials Symposium (IMSP´2014), Pamukkale University (Denizli, Turkey), 15./17. October 2014}, pages = {665 -- 679}, language = {en} } @inproceedings{KasparKleinerRabl, author = {Kaspar, Marcel and Kleiner, Florian and Rabl, Hans-Peter}, title = {Online-Analyse und Optimierung der Schmier{\"o}lverd{\"u}nnung bei direkteinspritzenden Ottomotoren}, series = {7. VDI-Fachtagung mit Fachausstellung Zylinderlaufbahn, Kolben, Pleuel : Baden-Baden, 03. und 04. Juni 2014}, booktitle = {7. VDI-Fachtagung mit Fachausstellung Zylinderlaufbahn, Kolben, Pleuel : Baden-Baden, 03. und 04. Juni 2014}, publisher = {VDI-Verlag}, address = {D{\"u}sseldorf}, isbn = {978-3-18-092230-0}, pages = {65 -- 77}, abstract = {Bei Ottomotoren mit Direkteinspritzung besteht beim Kaltstart, den Warmlaufphasen und auch durch den Einfluss anderer Parameter wie z. B. des Einspritzzeitpunkts oder des Einspritzdrucks die Problematik, dass Kraftstoff an die Zylinderlaufbahn aufgetragen wird und sich mit dem Motor{\"o}l vermischen kann. Eine Verst{\"a}rkung dieses Kraftstoffauftrags ist unter anderem der Verschiebung der Motorbetriebspunkte zu h{\"o}heren Mitteldr{\"u}cken und damit einem Wirkungsgrad optimaleren Betrieb geschuldet. Eine Ver{\"a}nderung der physikalischen und chemischen Eigenschaften des Motor{\"o}ls durch die Verd{\"u}nnung mit Kraftstoff ist die Folge. Durch die Verringerung der Viskosit{\"a}t des Motor{\"o}ls kann es zu einer verminderten Schmierwirkung des {\"O}ls kommen, die im schlimmsten Fall zur Sch{\"a}digung des Motors f{\"u}hrt. Existierende Offline-Analysemethoden die zeitintensive Laboranalysen nach sich ziehen, als auch Online-Messverfahren die nicht den technischen Anforderungen hinsichtlich Genauigkeit und einer kurzen Messdauer entsprechen, stellen aktuell die einzigen Messmethoden zur Bestimmung der Schmier{\"o}lverd{\"u}nnung dar. Durch neue Entwicklungstrends bei Ottomotoren ist es jedoch unbedingt notwendig, die Mechanismen des Kraftstoffein- und -austrags in das und aus dem Motor{\"o}l genauer zu untersuchen. Mit der an der OTH Regensburg neu entwickelten Messtechnik wurde eine Vorgehensweise erarbeitet, mit der die zeitlichen Verl{\"a}ufe des Kraftstoffein- und -austragsverhaltens bei Ottomotoren quantitativ in kurzer Zeit bestimmt und optimiert werden k{\"o}nnen. Especially at cold start and the warm-up operation GDI engines have an issue with oil dilution. Parameters such as injection timing and injection pressure impact the entry of fuel in the engine oil as well. With the adjustment of engine operating points to higher mean effective pressures resulting in downsizing concepts also an additional increase of fuel entry occurs. Fuel gets into the oil pan and is mixed with the engine oil so that the physical and chemical properties of the engine oil are changed. With the reduction of engine oil viscosity due to fuel entry a reduced lubricating effect can be caused. In the worst case damage to the engine occurs, To determine oil dilution online and offline measurement methods exist. A rather long analysis time in the laboratory is a disadvantage of the offline methods. Online methods are not correlating with technical requirements in terms of accuracy and a short measurement time. New trends in the development of gasoline engines require investigations of fuel in oil sorption and desorption processes. A new measurement technique which is developed at the OTH Regensburg enables to determine quantitative fuel in oil sorption and desorption processes. With this technique a procedure was generated to measure the oil dilution at gasoline engines and optimize them in a short time.}, language = {de} } @inproceedings{NonnErdelenPepplerWesseletal., author = {Nonn, Aida and Erdelen-Peppler, Marion and Wessel, Waldemar and Mahn, Denise}, title = {How reliable are the current testing procedures for the safety assurance against crack propagation in seamless gas pipelines}, series = {Proceedings of the ASME 2014 33rd International Conference on Ocean, Offshore and Arctic Engineering (OMAE2014), Volume 4A: Structures, Safety and Reliability, June 8-13, 2014, San Francisco, USA}, booktitle = {Proceedings of the ASME 2014 33rd International Conference on Ocean, Offshore and Arctic Engineering (OMAE2014), Volume 4A: Structures, Safety and Reliability, June 8-13, 2014, San Francisco, USA}, doi = {10.13140/2.1.3190.6567}, abstract = {The worldwide growing energy demand with the exploration of new gas fields has promoted the development of high toughness seamless pipeline steels which should sustain the increasing demands resulting from the complex loading situations. One of the most important prerequisites for safe installation and operation of long distance gas transmission pipelines is the detailed knowledge and characterization of their fracture performance for specific applications. However, recent industry experience has revealed concerns related to the limitations and reliability of current test methods for brittle-to-ductile transition evaluation. Regarding the transition temperature evaluation, the critical issues involve Drop-Weight Tear Testing (DWTT) and full-scale West-Jefferson (WJ) test applied to the smaller pipes with diameter less than 500mm. The DWTT leads frequently to invalid results in terms of abnormal fracture appearance and inverse fracture occurrence. It is still not clear if this behavior is only owed to a testing effect, which material characteristics cause it and how far it reflects the full-scale behavior. Similar observations were made for the West-Jefferson tests, which could not be assessed in the standard manner either. Again, the question was towards testing effects and the behavior of the pipeline transporting gaseous media remains unanswered. Therefore, this paper aims at identifying open questions on basis of a literature study and own experimental results and showing possible ways forward in demonstrating safety in design against propagating fracture.}, language = {en} } @inproceedings{NonnBrauer, author = {Nonn, Aida and Brauer, Holger}, title = {Establishing the correlation between impact energies for different sized specimens using damage models}, series = {Proceedings of the 10th International Pipeline Conference 2014 (IPC2014), September 29 - October 3, 2014, Calgary, Alberta, Canada, Vol. 3: Materials and joining, risk and reliability}, booktitle = {Proceedings of the 10th International Pipeline Conference 2014 (IPC2014), September 29 - October 3, 2014, Calgary, Alberta, Canada, Vol. 3: Materials and joining, risk and reliability}, doi = {10.1115/IPC2014-33164}, abstract = {The safety assessment of flawed pressurized pipes requires the knowledge of toughness properties which are usually provided in terms of impact energy from standard full-sized CVN notch specimens. For pipes with wall thickness less than 10mm different Charpy standards allow for the application of sub-sized specimens. However, it is still not fully clear how the impact energy from sub-sized specimens can be used to evaluate the fracture resistance of the pipes and how this energy correlates to the one from the full-sized specimen. Although different empirical correlations between sub-sized and full-sized specimens exist in the literature their validity is questionable since they are based on the results for older generation of steels. In the recent years the application of damage mechanics models has been promoted to assess the fracture behavior and deformation capacity of pipelines. The main advantage of these models can be found in their capability to link the damage evolution and the underlying stress/strain condition. In this paper damage mechanics approach is applied to describe fracture behavior of X65 pipeline material. Within the damage mechanics approach, Gurson-Tvergaard-Needleman (GTN) model is considered to be adequate for the simulation of ductile fracture. For brittle fracture, GTN model is extended by a propagation criterion which examines if the cleavage fracture stress is reached by the maximal principal stresses. The model parameters are calibrated and verified by means of load-displacement curves obtained from instrumented impact tests on different sized CVN specimens. This damage model is subsequently employed to simulate ductile-brittle transition behavior.}, language = {en} } @inproceedings{NonnErdelenPepplerWesseletal., author = {Nonn, Aida and Erdelen-Peppler, Marion and Wessel, Waldemar and Harksen, Silke and Mahn, Denise}, title = {How to assure fracture-propagation control for seamless gas pipelines?}, series = {Proceedings of the 2014 10th International Pipeline Conference (IPC2014), Volume 3: Operations, Monitoring, and Maintenance, Materials and Joining, September 29-October 3, 2014, Calgary, Canada}, booktitle = {Proceedings of the 2014 10th International Pipeline Conference (IPC2014), Volume 3: Operations, Monitoring, and Maintenance, Materials and Joining, September 29-October 3, 2014, Calgary, Canada}, doi = {10.1115/IPC2014-33169}, abstract = {Fracture propagation control in gas transmission gas pipelines belongs to the major design requirements for safe operation at high internal pressures. However, the current tests such as Drop-Weight-Tear Test (DWTT) and full-scale West-Jefferson (WJ) test reach the limits of their applicability with respect to transition temperature evaluation for seamless quenched and tempered small diameter pipes reflecting nowadays alloying concepts related to mechanical properties. Hereby, different geometry and material effects are evident which might lead to misinterpretation and unreliability of testing results. This paper aims to discuss open issues addressed in the literature and in own experimental findings with respect to reliability and transferability of testing methods, fracture parameters and their representativeness of seamless quenched and tempered pipeline behavior. By applying damage mechanics approach, it is possible to quantify the prevailing stress state and thus to understand the mechanisms controlling specific fracture appearance (ductile or brittle). Furthermore, studies were performed with objective to quantify the effect of different parameters (geometry, material and loading) on the fracture performance of the pipeline. The results from these investigations will serve as a basis for a safe pipeline design against propagating fracture.}, language = {en} } @inproceedings{KarbasianGrossWeegeNonnetal., author = {Karbasian, H. and Groß-Weege, J. and Nonn, Aida and Zimmermann, S. and Kalwa, Christoph}, title = {Assessment of collapse resistance of UOE pipes - comparison of full-scale and ring collapse tests}, series = {Proceedings of the 10th International Pipeline Conference 2014 (IPC 2014), September 29 - October 3, 2014, Calgary, Alberta, Canada}, booktitle = {Proceedings of the 10th International Pipeline Conference 2014 (IPC 2014), September 29 - October 3, 2014, Calgary, Alberta, Canada}, language = {en} } @inproceedings{BaumerKastenmeierEhrlich, author = {Baumer, A. and Kastenmeier, Andreas and Ehrlich, Ingo}, title = {Investigation of Bolted Composite Joints with Different Reinforcement Elements at the Bolt Hole}, series = {4th Applied Research Conference, 5th July 2014, Ingolstadt}, booktitle = {4th Applied Research Conference, 5th July 2014, Ingolstadt}, editor = {Ziemann, Olaf and Mottok, J{\"u}rgen and Pforr, Johannes}, publisher = {Shaker}, pages = {255 -- 258}, language = {en} } @inproceedings{FritzSchmidEhrlich, author = {Fritz, B. and Schmid, Vinzent and Ehrlich, Ingo}, title = {Analytical and numerical shear stress analysis of adhesive structural bonded joints under tension load}, series = {Applied Research Conference 2014 - ARC 2014, 5th July 2014, Ingolstadt}, booktitle = {Applied Research Conference 2014 - ARC 2014, 5th July 2014, Ingolstadt}, editor = {Ziemann, Olaf and Mottok, J{\"u}rgen and Pforr, Johannes}, publisher = {Shaker}, address = {Aachen}, pages = {266 -- 271}, language = {de} }