TY - JOUR A1 - Schubert, Martin J. W. T1 - 70V-to-5V Differential CMOS Input Interface JF - IEE Electronic Letters Y1 - 1994 U6 - https://doi.org/10.1049/el:19940235 VL - 30 IS - 4 SP - 296 EP - 297 ER - TY - CHAP A1 - Declerq, Michel A1 - Schubert, Martin J. W. A1 - Clément, F. T1 - 5V-to-75V CMOS Output Interfaces T2 - Proceedings of the1993 IEEE International Solid-State Circuits Conference (ISSCC), Feb. 24-26 1993, San Francisco, CA, USA N2 - A family of CMOS low- to high-voltage output interface circuits based on a standard, unmodified low-voltage CMOS technology is described. Using only thin-oxide high-voltage (HV) devices with reduced V/sub GS/ (gate-to-source voltage) swing, it makes use of level-shift techniques to meet the constraints on the gate control signals. These static circuits permit the full output voltage swing of V/sub DDH/, while keeping the V/sub GS/ swing of the output devices within the safety limits, including during HV supply transients. Using a standard 2- mu m n-well CMOS technology, reliable, reproducible V/sub DS/ breakdown voltages as high as 120 V and 80 V have been obtained for HV-nMOS and HV-pMOS devices, respectively.< > Y1 - 1993 U6 - https://doi.org/10.1109/ISSCC.1993.280014 SP - 162 EP - 163 ER - TY - JOUR A1 - Schubert, Martin J. W. A1 - Höfflinger, Bernd A1 - Zingg, René P. T1 - An Analytical Model for Strongly Inverted and Accumulated Silicon Films JF - Solid-State Electronics N2 - An analytical model for the spatial distribution of potential, electric field and carrier densities is presented, assuming uniform doping density and constant quasi-Fermi potentials in the direction of modeling. Starting from the current relations a differential equation respecting two-dimensional effects is developed and solved approximately by decomposition in three regions with different preconditions: (a) flatband region, (b) constant spacecharge density and (c) strong inversion or accumulation. Inaccuracies arise mainly from violated preconditions at the interfaces between the different regions. Two-dimensional effects are respected in the analytical model of (b) only but they influence region (c) by means of boundary conditions at the interface of (b) and (c). The investigations of this paper are focused to region (c). This part of our model is identical to the model of Hauser and Littlejohn[1]. They integrated a simplified form of the semiconductor-Poisson equation twice but were restricted to one-dimensional applications and thermal equilibrium. Our derivation allows for large electric fields and current densities perpendicular to the direction of modeling. From analytical considerations confirmed by numerical experiments we suggest preference to the gradual channel condition, with x and y defined according to Fig. 1. This definition allows the potentials to vary significantly with respect to y. We found that this holds for the quasi-Fermi potentials also. Furthermore an empirical model for the maximum width of strong-inversion layers in uniformly doped silicon films is presented in eqn (46). Y1 - 1990 U6 - https://doi.org/10.1016/0038-1101(90)90136-3 VL - 33 IS - 12 SP - 1553 EP - 1567 PB - Elsevier ER - TY - CHAP A1 - Schubert, Martin J. W. T1 - Mixed Signal Modeling in VHDL by Distributed Local Iteration T2 - VHDL Form, Toledo, Spain, April 20-24, 1997 Y1 - 1997 ER - TY - CHAP A1 - Declerq, Michel A1 - Clément, F. A1 - Schubert, Martin J. W. A1 - Harb, Adnan A1 - Dutoit, Michel T1 - Design and Optimization of High-Voltage CMOS Devices Compatible wih a Standard 5V CMOS Technology T2 - Proceedings of IEEE Custom Integrated Circuits Conference, May 9-12 1993, San Diego, CA, USA N2 - High-voltage n- and p-MOSFETs fully compatible with a standard 5 V CMOS technology have been designed, optimized, and fabricated. No process changes are required. By modifying the logical equations generating one of the physical masks from the design masks, a p-type buffer region for the high-voltage p-MOS was easily implemented. This modification does not affect the low-voltage part of the circuits. These high-voltage devices have been used successfully as output drivers in semicustom arrays, and as building blocks for custom low- to high-voltage output interfaces. Aspects of reliability, device protection, and circuit design techniques are addressed. Y1 - 1993 SN - 0-7803-0826-3 U6 - https://doi.org/10.1109/CICC.1993.590766 SP - 24.6.1 EP - 24.6.4 ER - TY - THES A1 - Schubert, Martin J. W. T1 - Eindimensionale Modellierung von SOI MOSFETs Y1 - 1991 CY - Hamburg ER - TY - JOUR A1 - Schubert, Martin J. W. A1 - Höfflinger, Bernd A1 - Zingg, René P. T1 - A One-Dimensional Analytical Model for the Dual-Gate-Controlled Thin-Film SOI MOSFET JF - IEEE Electron Device Letters N2 - A one-dimensional analytical model for dual-gate-controlled SOI MOSFETs is presented and applied to a stacked p-channel MOSFET fabricated by epitaxial lateral overgrowth (ELO). The authors found and modeled a nonlinear dependence of front-gate threshold voltage on back-gate voltage if threshold is defined by a constant current instead of a constant silicon-surface potential. It is demonstrated by comparison of subthreshold slopes that surface potentials are not pinned to the onset of strong inversion or accumulation. Accurate one-dimensional modeling is a necessity for device characterization and a precondition for general SOI models for circuit simulation.< > Y1 - 1991 U6 - https://doi.org/10.1109/55.116927 VL - 12 IS - 9 SP - 489 EP - 491 ER - TY - CHAP A1 - Schubert, Martin J. W. A1 - Höfflinger, Bernd A1 - Zingg, René P. T1 - A New Analytical Charge Model for the Dual-Gate-Controlled Thin-Film SOI MOSFET T2 - Superlattices and Microstructures N2 - An analytical model for dual-gate-controlled SOI MOSFETs is presented, assuming uniformly doped p-silicon films. It is restricted to electron inversion layers and depletion regions, neglecting hole densities. It allows to account for the spatial description of electronic quantities in the silicon film. Due to the non-linearities of the semiconductor equations the model parameters must be extracted iteratively. Some applications are presented to demonstrate the usefulness of the model. Y1 - 1990 U6 - https://doi.org/10.1016/0749-6036(90)90218-V VL - 7 IS - 4 SP - 323 EP - 326 PB - Elsevier ER - TY - THES A1 - Spirkl, Florian T1 - Vergleichende rechnerische Untersuchungen zur Lastaufteilung und Setzungen von Stabilisierungssäulen mit Lasttransferschichten N2 - Die Erschließung von Neubauflächen, steigende Bauwerkslasten und strengere Anforderungen an Setzungen und Setzungsdifferenzen führen zu einem steigenden Bedarf an Tiefgründungsmaßnahmen. Eine relativ junge Entwicklung auf diesem Gebiet ist die Anwendung von Stabilisierungssäulen (StS) und pfahlähnlichen Tragelementen als Alternative zur konventionellen Pfahlgründung. Auf Grund der im Vergleich zum Pfahl geringeren Tragfähigkeit der StS werden diese zumeist als „Säulenwald“ angeordnet und die abzutragende Last über eine Lasttransferschicht (LTS) auf die einzelnen StS abgeleitet. Zusätzlich wird häufig eine oder mehrere Geogitterlagen eingebracht, was zur Erhöhung des Lastanteils der StS führt. Ein gängies Anwendungsbeispiel hierfür ist z.B. die Gründung eines Damms. Über die Lastaufteilung zwischen StS und anstehender Weichschicht wurden im Laufe der Jahre verschiedenste Theorien und Berechnungsansätze veröffentlicht. Zunächst wird eine Auswahl verschiedener geschlossener Berechnungsansätze für den 3-dimensionalen Fall vorgestellt und miteinander verglichen. Diesen ist gemein, dass für die Lastaufteilung lediglich die bodenmechanischen Eigenschaften der LTS und die geometrischen Parameter benötigt werden. Eine Berücksichtigung der anstehenden Weichschicht ist z.B. bei der iterativen Berechnung mittels Lasttransfermethode oder bei FE-Berechnungen möglich. Diese Ansätze werden, da durch die Berücksichtigung der Eigenschaften der Weichschicht weitere Freiheitsgrade entstehen, gesondert miteinander verglichen. Abschließend wird an Hand zweier Beispiele die Komplexität der Problemstellung „Ermittlung der Laustaufteilung zwischen StS und WS“ aufgezeigt. KW - Geotechnik KW - Stabilisierungssäule KW - Lasttransferschicht Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-15713 CY - Regensburg ER - TY - CHAP A1 - Romano, Marco A1 - Micklitz, Matthias A1 - Olbrich, Florian A1 - Bierl, Rudolf A1 - Ehrlich, Ingo A1 - Gebbeken, Norbert T1 - Experimental investigation of damping properties of unidirectionally and fabric reinforces plastics by the free decay method T2 - Proceeding of the 15th International Materials Symposium (IMSP´2014), Pamukkale University (Denizli, Turkey), 15./17. October 2014 Y1 - 2014 SP - 665 EP - 679 ER - TY - CHAP A1 - van der Weerd, Bastiaan A1 - Bierl, Rudolf A1 - Matysik, Frank-Michael T1 - A Conductivity Probe for the Determination of Carbon Dioxide Tension at the Oxygenator Exhaust Outlet during Extracorporeal Membrane Oxygenation (ECMO) T2 - Electrochemistry 2014, September 22 - 24, Mainz Y1 - 2014 ER - TY - GEN A1 - van der Weerd, Bastiaan A1 - Bierl, Rudolf A1 - Matysik, Frank-Michael T1 - A Conductivity Probe for Determination of the Carbon Dioxide Tension at the Oxygenator Exhaust Outlet during Extracorporeal Membrane Oxygenation (ECMO) T2 - Proceedings of the 9th ISC Modern Analytical Chemistry 2013, Prag Y1 - 2013 UR - https://www.gdch.de/fileadmin/downloads/Veranstaltungen/Tagungen/2014_Tagungen/analytica/poster_abstracts/sens03_vanderweerd_5860.pdf ER - TY - GEN A1 - Rück, Thomas A1 - Hofmann, Matthias A1 - Bierl, Rudolf T1 - Development of a miniaturized photoacoustic multigas sensing system for trace gas measurement T2 - 17th International Conference on Photoacoustic and Photothermal Phenomena, Oct. 20-24, 2013, Suzhou China Y1 - 2013 UR - https://www.gdch.de/fileadmin/downloads/Veranstaltungen/Tagungen/2014_Tagungen/analytica/poster_abstracts/sens05_rueck_5925.pdf ER - TY - CHAP A1 - van der Weerd, Bastiaan A1 - Bierl, Rudolf A1 - Matysik, Frank-Michael T1 - A Conductivity Probe for the Determination of Carbon Dioxide Tension at the Oxygenator Exhaust Outlet during Extracorporeal Membrane Oxygenation (ECMO) T2 - analytica Conference 2014, 1. bis 4. April, München Y1 - 2014 ER - TY - CHAP A1 - Hofmann, Matthias A1 - Bierl, Rudolf A1 - Rück, Thomas T1 - Implementation of a dual-phase lock-in amplifier on a TMS320C5515 digital signal processor T2 - Proceedings of the 5th European DSP Education and Research Conference (EDERC), 13-14 Sept. 2012, Amsterdam N2 - A digital dual-phase lock-in amplifier that is capable to run on a low-cost, low-power platform comprising a 16-bit fixed-point digital signal processor was developed. This is achieved by a set of optimised digital filters including an exponential averager to adjust the time constant of the overall filter. The reference frequency is generated using a direct digital synthesis source utilising angle decomposition with a resolution of 1 Hz. The digital lock-in algorithm is described and the performance of the algorithm is analysed. The experimental results show that the developed lock-in amplifier achieves similar performance to a commercially available lock-in amplifier. Y1 - 2012 U6 - https://doi.org/10.1109/EDERC.2012.6532217 ER - TY - RPRT A1 - Unger, J. A1 - Rück, Thomas A1 - Landgraf, Ferdinand A1 - Bierl, Rudolf T1 - Herstellung und Analyse der Resonanzfrequenz eines MEMS Cantilever für das CEPAS Verfahren N2 - Diese Abhandlung beschreibt das Konzept eines mikroeletromechanischen Systems (MEMS), das im Messverfahren der cantilever enhanced photoacoustic spectroscopy (CEPAS) Verwendung finden soll. Es wird die Herstellung eines einseitig eingespannten Biegebalkens aus Silizium mittels deep reactiv ion etching (DRIE) beschrieben. Des Weiteren wird die Resonanzfrequenz dieses Cantilevers mit Hilfe Laservibrometertechnik untersucht. Die resultierenden resonanten Schwingungen 0.Ordnung werden mit den Ergebnissen einer vereinfachten theoretischen Näherung verglichen. Die Messergebnisse stehen in gutem Zusammenhang mit den theoretischen Werten. Solche Cantilever, die aus silicon on insula tor (SOI) Wafer angefertigt wurden, weisen bei einer Zielfrequenz ein mittlere Abweichung von Δf = 118±26Hz (bzw.Δf =0,76±0,17%) auf. Y1 - 2015 ER - TY - JOUR A1 - Romano, Marco A1 - Micklitz, Matthias A1 - Olbrich, Florian A1 - Bierl, Rudolf A1 - Ehrlich, Ingo A1 - Gebbeken, Norbert T1 - Experimental investigation of damping properties of unidirectionally and fabric reinforced plastics by the free decay method JF - Journal of Achievements in Materials and Manufacturing Engineering N2 - Purpose: of this paper is experimental investigation of damping properties of unidirectionally and fabric reinforced plastics by the free decay method. Design/methodology/approach: For the evaluation of the presumed effect experimental structural dynamic investigations comparing unidirectionally and fabric reinforced plastics are carried out. In detail the free decay behaviour of flat beamlike specimens under fixed-free boundary conditions and relatively constant and reproducible displacement excitation is investigated. Findings: The vibrating structure has been measured by a laser scanning vibrometer PSV 400 from POLYTEC. In both cases evaluation of the results yields enhanced damping properties of the specimens with fabric reinforcement compared to the unidirectionally reinforced specimens. The results justify the presumed acting of a mesomechanic kinematic. Research limitations/implications: The results show that in either case the material damping in terms of the logarithmic decrement of the fabric reinforced material is higher than the material damping in of the unidirectionally reinforced material. Additionally, when the fabric reinforced specimens are addressed, in each case the plain weave reinforced specimens exhibited higher values of the material damping as the twill weave 2/2 reinforced ones. Originality/value: Ondulations in fabrics as a textile semi-finished product are caused by the alternating crossing of warp and fill yarns. In the mesoscopic scale the acting of a mesomechanic kinematic is presumed to enhance the damping properties under cyclic elastic deformation. For the evaluation of the presumed effect experimental structural dynamic investigations comparing unidirectionally and fabric reinforced plastics are carried out. KW - structural vibration KW - damping KW - fibre reinforced plastics KW - mesomechanic scale KW - fabric reinforced layer Y1 - 2014 VL - 63 IS - 2 SP - 65 EP - 80 ER - TY - CHAP A1 - Eisenried, Michael A1 - Romano, Marco A1 - Jungbauer, Bastian A1 - Ehrlich, Ingo A1 - Gebbeken, Norbert ED - Ziemann, Olaf ED - Bogner, Werner ED - Mottok, Jürgen T1 - Influence of parameters of the production process on the material quality of unidirectionally reinforced prepregs T2 - Applied Research Conference 2013, ARC 2013 ; 17th and 18th October 2013, Deggendorf Y1 - 2013 SP - 70 EP - 75 PB - Shaker CY - Aachen ER - TY - CHAP A1 - Bruland, Matthias A1 - Schmid, Vinzent A1 - Ehrlich, Ingo ED - Ziemann, Olaf ED - Mottok, Jürgen ED - Pforr, Johannes T1 - Analyzing and Testing of a Single Solution of Self-cutting Thread Inserts in Composites T2 - Applied Research Conference 2014 - ARC 2014, 5th July 2014, Ingolstadt Y1 - 2014 SP - 286 EP - 288 PB - Shaker ER - TY - CHAP A1 - Hoinkes, Carl J. J. A1 - Romano, Marco A1 - Ehrlich, Ingo A1 - Höcherl, Johannes A1 - Gebbeken, Norbert ED - Ziemann, Olaf ED - Mottok, Jürgen ED - Pforr, Johannes T1 - Investigation of fibre reinforced plastics with monolithic and hybrid stacking sequences under high-velocity impact loads T2 - Applied Research Conference 2014 - ARC 2014, 5th July 2014, Ingolstadt Y1 - 2014 PB - Shaker CY - Aachen ER - TY - CHAP A1 - Valentino, Piergiorgio A1 - Romano, Marco A1 - Ehrlich, Ingo A1 - Furgiuele, Franco A1 - Gebbeken, Norbert ED - Iacovello, F. ED - Risitano, G. ED - Susmel, L. T1 - Mechanical characterization of basalt fibre reinforced plastic with different fabric reinforcements – Tensile tests and FE-calculations with representative volume elements (RVEs) T2 - Acta Fracturae - XXll Convegno Nazionale IGF (Italiano Gruppo Frattura) N2 - 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. Y1 - 2013 UR - http://www.gruppofrattura.it/pdf/convegni/22/IGFXXII/index.html#/242/ ER - TY - CHAP A1 - Ibanez Gomez, D. A1 - Kastenmeier, Andreas A1 - Ehrlich, Ingo ED - Ziemann, Olaf ED - Mottok, Jürgen ED - Pforr, Johannes T1 - Development and construction of a winding machine for the production of composite tubes T2 - 4th Applied Research Conference - ARC 2014, 5th July 2014, Ingolstadt Y1 - 2014 SP - 315 EP - 318 PB - Shaker CY - Aachen ER - TY - CHAP A1 - Siegl, Marco A1 - Rieger, David A1 - Kovárík, Tomáš A1 - Ehrlich, Ingo T1 - Long-Term Behavior of Thermoplastics under UV Light tested by a self-build Device T2 - 3. OTH-Clusterkonferenz, 13. April 2018, Weiden, Tagungsband; Festschrift, 5 Jahre OTH-Verbund N2 - This article presents first results of artificial aging experi-ments by ultraviolet (UV) irradiation on thermoplasticmaterials conducted as an intent of the research project Thermoplastic Composite Structures (TheCoS) in colla-boration of the Ostbayerische Technische Hochschule(OTH) Regensburg and the University of West Bohemia(UWB) in Pilsen as part of a cross-border cooperation. In technical applications, thermoplastic materials are oftenaffected by aging and a related deterioration of the mechanical properties. Therefore, it is necessary to identifythe aging behavior of thermoplastic materials. For this,experiments were performed for three thermoplasticmaterials, namely polypropylene (PP), ultra high mole -cular weight polyethylene (UHMWPE) and high impactstrength polystyrene (HIPS). For these experiments, a UV chamber was constructed according to the internationalstandard EN ISO 4892-3 for simulation of exposurebehind window glass. The results are evaluated by testing the flexural strength and the dynamic mechanicalresponse after a selected period of time under UV lightand then compared to untreated test specimens. Y1 - 2018 UR - https://www.oth-regensburg.de/fileadmin/media/forschung/Dateien_2018/Clusterkonferenz-Tagungsband-2018.pdf SP - 118 EP - 122 ER - TY - CHAP A1 - Niebauer, M. A1 - Schmid, Vinzent A1 - Ehrlich, Ingo ED - Mottok, Jürgen ED - Reichenberger, Marcus ED - Scharfenberg, J. ED - Ziemann, Olaf T1 - Failure Criteria of Adhesively Bonded Joints BT - A Review T2 - Applied Research Conference 2015 - ARC 2015, Nürnberg, 3rd July 2015 - 16. Juli 2015 Y1 - 2015 SN - 978-3863869458 SP - 347 EP - 351 PB - Pro Business Verlag CY - Berlin ER - TY - CHAP A1 - Romano, Marco A1 - Hoinkes, Carl J. J. A1 - Ehrlich, Ingo A1 - Höcherl, Johannes A1 - Gebbeken, Norbert ED - Meran, C. T1 - Influence of the impactor on the experimentally determined energy dissipation properties of fiber-reinforced plastics with hybrid layups under high velocity impact loads T2 - Proceeding of the 15th International Materials Symposium (IMSP´2014), Pamukkale University (Denizli, Turkey), 15./17. October 2014 Y1 - 2014 SP - 650 EP - 664 ER - TY - CHAP A1 - Niedernhuber, Michal A1 - Ehrlich, Ingo A1 - Holtmannspötter, Jens ED - Ziemann, Olaf ED - Mottok, Jürgen ED - Pforr, Johannes T1 - Fiber-Oriented Repair of Fiber Reinforced Plastics: Investigations on Tensile Specimens T2 - 4th Applied Research Conference - ARC 2014, 5th July 2014, Ingolstadt Y1 - 2014 SP - 298 EP - 302 PB - Shaker CY - Aachen ER - TY - CHAP A1 - Ehrlich, Ingo A1 - Dinnebier, Heinrich A1 - Jost, C. ED - Meran, C. T1 - Comparison of Impact Delaminations in CFRP Using Ultrasonic Testing, Microfocus Computed X-Ray Tomography and Micrographic Cross-Section T2 - Proceeding of the 15th International Materials Symposium (IMSP´2014), Pamukkale University (Denizli, Turkey), 15./17. October 2014 Y1 - 2014 SP - 441 EP - 450 ER - TY - CHAP A1 - Dinnebier, Heinrich A1 - Ehrlich, Ingo ED - Meran, C. T1 - The Effects of Severe Temperature Changes and High Humidity on Porous CFRP T2 - Proceedings of the 15th International Materials Symposium (IMSP´2014), Pamukkale University (Denizli, Turkey), 15./17. October 2014 N2 - Purpose: A route to manufacture porous carbon fiber reinforced plastic (CFRP) for study purposes is described. Design/methodology/approach: The porous CFRP is characterized using standard techniques such as matrix digestion as well as the more sophisticated method of high resolution Microfocus X-Ray Tomography (μCT). A comparison of the results of those methods is presented. The mass gains of specimens with a wide range of porosity have been measured both in constant humidity and in alternating environments. Findings: It could be shown that severe temperature changes can temporarily increase the moisture content of porous CFRP. However, after the return to a constant environment, the moisture content returns back to saturation levels. Furthermore, it could be shown by X-Ray Tomography that even under severe climatic conditions no permanent liquid water condensates inside the pores. Research limitations/implications: Using Microfocus Computed Tomography it could be shown that even after nearly a year under hot-wet conditions and more than 150 severe temperature cycles there is no liquid water detectable inside the pores. Originality/value: In this paper the effects of severe temperature changes and high humidity on porous CFRP. Y1 - 2014 UR - http://jamme.acmsse.h2.pl/vol67_1/6712.pdf SP - 433 EP - 440 ER - TY - CHAP A1 - Ottawa, Patrycja A1 - Romano, Marco A1 - Ehrlich, Ingo A1 - Wagner, Marcus A1 - Gebbeken, Norbert T1 - The influence of ondulation in fabric reinforced composites on dynamic properties in a mesoscopic scale T2 - 11. LS-DYNA Forum, 9. - 10. Oktober 2012, Ulm N2 - 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. Y1 - 2012 UR - https://www.dynamore.de/de/download/papers/dynamore/de/download/papers/ls-dyna-forum-2012/documents/materials-5-2 SP - 171 EP - 172 ER - TY - CHAP A1 - van der Weerd, Bastiaan A1 - Bierl, Rudolf A1 - Matysik, Frank-Michael T1 - A Planar Conductivity Probe for CO2 Determination at the Oxygenator Outlet T2 - Doktorandenseminar GDCh Prozessanalytik 2014, Berlin Y1 - 2014 ER - TY - CHAP A1 - Nonn, Aida A1 - Brauer, Holger T1 - Establishing the correlation between impact energies for different sized specimens using damage models T2 - 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 N2 - 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. Y1 - 2014 U6 - https://doi.org/10.1115/IPC2014-33164 ER - TY - CHAP A1 - Jobst, Simon A1 - Bierl, Rudolf T1 - A Comparison of Correlation and Zero-Crossing Based Techniques in Ultrasonic Measurement T2 - 10th International Symposium on Applied Reconfigurable Computing (ARC'2014), Vilamoura, Algarve, Portugal, 14 - 16 April, 2014 N2 - Ultrasound measurement technology has advancedin previous decades due to positive developments in computing power and lower cost for the necessary hardware. Correlation-based processing can be advantageous for high-accuracy measurements, especially in noisy environments. Higher computational load makes correlation less attractive for industrialapplications, though, favouring traditional processing techniques. A platform for comparing various processing techniques hasbeen developed. It was found that both zero-crossing detectionas well as correlation can achieve very high accuracy over a hightemperature range but that correlation-based processing can lead to a significant precision bias depending on system bandwidth. Y1 - 2014 ER - TY - CHAP A1 - Rück, Thomas A1 - Landgraf, Ferdinand A1 - Läpple, I. A1 - Unger, J. A1 - Matysik, Frank-Michael A1 - Bierl, Rudolf T1 - Specification of an improved photoacoustic setup for high-sensitive, low-cost NO2 trace gas detection T2 - 18th International Conference on Photoacoustic and Photothermal Phenomena (ICPPP18), 2015, September 6-10, Novi Sad, Serbia Y1 - 2015 ER - TY - GEN A1 - Rück, Thomas A1 - Matysik, Frank-Michael A1 - Bierl, Rudolf T1 - Development of a miniaturized photoacoustic multigas sensing system for trace gas measurement T2 - analytica conference 2014, 1. bis 4. April, München Y1 - 2014 UR - https://www.gdch.de/fileadmin/downloads/Veranstaltungen/Tagungen/2014_Tagungen/analytica/poster_abstracts/sens05_rueck_5925.pdf ER - TY - CHAP A1 - Hausler, Peter A1 - Holler, Sven A1 - Hirsch, Thomas A1 - Bierl, Rudolf T1 - High integrated miniaturized sensor based on Surface Plasmon Resonance T2 - International Biosensor Conference, 11th Workshop on Biosensors & Bioanalytical Microtechniques in Environmental, Food & Clinical Analysis, BBMEC 11, 26.-30. September 2015, Regensburg, Germany Y1 - 2015 ER - TY - CHAP A1 - Nonn, Aida A1 - Cerrone, Albert R. A1 - Stallybrass, C. A1 - Meuser, H. T1 - Microstructure-based modeling of high-strength linepipe steels T2 - 6th Pipeline Technology Conference 2013, 6-9 October, Ostend, Belgium N2 - 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. Y1 - 2013 U6 - https://doi.org/10.13140/2.1.2797.4404 ER - TY - CHAP A1 - Nonn, Aida A1 - Kalwa, Christoph T1 - Application of damage mechanics approach for crack propagation in pipeline T2 - 19th Biennial Joint Technical Meeting (JTM) on Pipeline Research, April 29 - May 3, 2013, Sydney, Australia Y1 - 2013 ER - TY - CHAP A1 - Schneider, Ingo A1 - Nonn, Aida A1 - Völling, Alexander A1 - Mondry, A. A1 - Kalwa, Christoph T1 - A damage mechanics based evaluation of dynamic fracture resistance in gas pipelines T2 - Procedia Materials Science, Volume 3 N2 - Investigation of running ductile fracture in gas transmission pipelines and the derivation of reliable crack arrest prediction methods belong to major topics in pipeline research. The yet available crack arrest criterion, known as the Battelle Two-Curve Method (BTCM), leads to reliable predictions up to grade X70 line pipe steels for which it has been validated. This includes specific limits in terms of mechanical properties, pressure and geometry. The application of this criterion to modern pipeline steels, i.e. especially grades X80 and beyond in combination with larger diameters and high pressure, has led to mispredictions of the BTCM. Hence, in order to ensure safe design of pipelines, new methods are required based on in depth knowledge and appropriate characterization of material resistance. This paper presents a procedure for the assessment of dynamic ductile fracture resistance based on combined experimental and numerical investigations. The procedure involves quasi-static and dynamic drop- weight tear testing (DWTT) on modified specimens with pre-fatigued crack for grades X65, X80 and X100 materials, and the application of cohesive zone (CZ) and Gurson-Tveergard-Needleman (GTN) models to describe ductile material damage. The damage model parameters are calibrated on basis of DWTT results and subsequently used to simulate dynamic crack propagation in a pipeline. The influence of material properties (strain hardening, toughness), pipe geometry, usage factor and decompression behaviour on ductile fracture propagation behaviour is studied and evaluated. The results will contribute to an enhanced understanding of major parameters controlling ductile fracture propagation and will help to establish a reliable procedure for safe design of new high-capacity pipelines with regard to crack arrest. KW - Pipeline KW - Dynamic ductile fracture KW - Crack arrest KW - Cohesive zone model KW - DWT testing Y1 - 2014 U6 - https://doi.org/10.1016/j.mspro.2014.06.315 VL - 3 SP - 1956 EP - 1964 ER - TY - CHAP A1 - Nonn, Aida T1 - Failure modeling of hybrid-laser welds in transition temperature region T2 - 18th European Conference on Fracture, Fracture of Materials and Structures from Micro to Macro Scale, August 30 - September 03, 2010 Dresden, Germany Y1 - 2010 CY - Dresden ER - TY - CHAP A1 - Nonn, Aida A1 - Kalwa, Christoph T1 - Analysis of dynamic ductile fracture propagation in pipeline steels BT - a damage mechanics approach T2 - 6th Pipeline Technology Conference (2013), Ostend, Belgium N2 - 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. Y1 - 2013 U6 - https://doi.org/10.13140/2.1.4370.3046 ER - TY - CHAP A1 - Nonn, Aida A1 - Kalwa, Christoph T1 - Application of probabilistic fracture mechanics for safety assessment of longitudinally welded linepipes T2 - 6th Pipeline Technology Conference (2013), Ostend, Belgium Y1 - 2013 ER - TY - JOUR A1 - Dinnebier, Heinrich A1 - Ehrlich, Ingo T1 - The effects of severe temperature changes and high humidity on porous CFRP JF - Journal of Achievements in Materials and Manufacturing Engineering (JAMME) N2 - Purpose: A route to manufacture porous carbon fiber reinforced plastic (CFRP) for study purposes is described. Design/methodology/approach: The porous CFRP is characterized using standard techniques such as matrix digestion as well as the more sophisticated method of high resolution Microfocus X-Ray Tomography (μCT). A comparison of the results of those methods is presented. The mass gains of specimens with a wide range of porosity have been measured both in constant humidity and in alternating environments. Findings: It could be shown that severe temperature changes can temporarily increase the moisture content of porous CFRP. However, after the return to a constant environment, the moisture content returns back to saturation levels. Furthermore, it could be shown by X-Ray Tomography that even under severe climatic conditions no permanent liquid water condensates inside the pores. Research limitations/implications: Using Microfocus Computed Tomography it could be shown that even after nearly a year under hot-wet conditions and more than 150 severe temperature cycles there is no liquid water detectable inside the pores. Originality/value: In this paper the effects of severe temperature changes and high humidity on porous CFRP. Y1 - 2014 VL - 67 IS - 1 SP - 14 EP - 20 ER - TY - CHAP A1 - Kofiani, Kirki A1 - Nonn, Aida A1 - Wierzbicki, Tomasz A1 - Kalwa, Christoph A1 - Walters, Carey T1 - Experiments and fracture modeling of high-strength pipelines for high and low stress triaxiality T2 - 22nd International Society of Offshore and Polar Engineering 2012 (ISOPE 2012), Rhodes, Greece, June 2012 N2 - 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. Y1 - 2012 ER - TY - THES A1 - Ehrlich, Ingo T1 - Impactverhalten schwach gekrümmter Strukturen aus faserverstärkten Kunststoffen Y1 - 2004 UR - https://d-nb.info/973886102/34 CY - München ER - TY - JOUR A1 - Kastenmeier, Andreas A1 - Schmid, Vinzent A1 - Ehrlich, Ingo A1 - Petratos, P. A1 - Mourtos, N. A1 - Trafalis, T. T1 - Specimen Preparation and Material Characterization of Filament Wound GFRP Composite Tubes JF - Athens Journal of Technology & Engineering N2 - Filament wound composite structures are widely used in the field of pressure vessels, tubes, pipelines or rocket cases. The mechanical behavior of these structures is typically different from those of flat laminated structures due to an alternating lay-up sequence, winding tension and manufacturing induced imperfections. However, design and analysis issues require the same engineering data as used for laminated structures in general. It has therefore become necessary to establish an accompanying quality assurance procedure following the production process to identify the material properties of the manufactured tubes especially for the single layer. Consequently, there are three different approaches of determining the elastic moduli and tensile strengths of a filament wound laminate. Either specimens are resected from a curved tube, from a tube with plane areas or standardized flat specimens are manufactured under deviating production conditions. All approaches entail disadvantages, whether in terms of manufacturing or testing parameters including geometry, lay-up sequence, porosity, fiber tension and load direction. This study presents the discrepancies in the determination of mechanical properties of a filament wound glass-fiber-reinforced polymer tube on curved or cylindrical specimens and flat specimens produced to meet the specifications of international standards. In order to obtain material properties not only in longitudinal but also in transverse direction of the tubes, the so-called split-disk tensile test modeled after ASTM Standard D 2290, is used with tube segments.The procedures of specimen production and preparation are described in detail. Material properties such as the fiber volume and void content of the composite specimens are conducted in order to consider quality and production differences. Finally tensile tests are performed and the results are compared and discussed. KW - Composite KW - Fiber-reinforced polymer KW - Filament winding KW - Split-disk KW - Tensile tests KW - Tubes Y1 - 2017 UR - https://www.athensjournals.gr/technology/2017-4-3-2-Kastenmeier.pdf VL - 4 IS - 3 SP - 191 EP - 205 ER - TY - JOUR A1 - Bode, J. A1 - Ehrlich, Ingo T1 - Entwicklung eines finiten Elements für Sandwichanwendungen JF - Zeitschrift für Angewandte Mathematik und Mechanik (ZAMM), Journal of Applied Mathematics and Mechanics Y1 - 1997 VL - 77 IS - 1 SP - 41 EP - 42 ER - TY - RPRT A1 - Eisenried, Michael A1 - Romano, Marco A1 - Jungbauer, Bastian A1 - Ehrlich, Ingo A1 - Gebbeken, Norbert T1 - Herstellung von unidirektional verstärkten Prepregs im Labormaßstab – Einfluss von Fertigungsparametern auf die Materialqualität T2 - Forschungsbericht 2013 / Ostbayerische Technische Hochschule Regensburg Y1 - 2013 UR - https://doi.org/10.35096/othr/pub-799 SP - 51 EP - 52 CY - Regensburg ER - TY - JOUR A1 - Pongratz, Christian A1 - Schlamp, Matthias A1 - Jungbauer, Bastian A1 - Ehrlich, Ingo A1 - Petratos, P. A1 - Mourtos, N. T1 - Detection of Delamination Damages in Thin Composite Plates using Noncontact Measurement of Structural Dynamic Behavior JF - Athens Journal of Technology & Engineering Y1 - 2016 U6 - https://doi.org/10.30958/AJTE.3-4-3 VL - 3 IS - 4 SP - 315 EP - 331 ER - TY - CHAP A1 - Paredes, Marcelo A1 - Keim, Vincent A1 - Nonn, Aida A1 - Wierzbicki, Tomasz T1 - Effect of plasticity parameter on the crack propagation in steel pipelines T2 - Proceedings of the conference on Technology for future and ageing piplines, Ghent, Belgium Y1 - 2018 ER - TY - CHAP A1 - Nonn, Aida A1 - Kalwa, Christoph T1 - Failure modeling of pipeline X100 Material in temperature transition region T2 - 22nd International Society of Offshore and Polar Engineering 2012 (ISOPE 2012), Rhodes, Greece N2 - 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. Y1 - 2012 ER -