@inproceedings{BohmannSchlampEhrlich, author = {Bohmann, T. and Schlamp, Matthias and Ehrlich, Ingo}, title = {Analysis of the Acoustic Emission Failure Frequencies of Glass Fiber Reinforced Composite Components}, series = {Applied Research Conference 2017 - ARC, 7 July 2017, M{\"u}nchen}, booktitle = {Applied Research Conference 2017 - ARC, 7 July 2017, M{\"u}nchen}, editor = {Klippel, Clemens and Mottok, J{\"u}rgen and Reichenberger, Marcus}, publisher = {Book-on-demand Verlag}, address = {Norderstedt}, pages = {369 -- 373}, language = {en} } @inproceedings{SchmidBrulandEhrlichetal., author = {Schmid, Vinzent and Bruland, Matthias and Ehrlich, Ingo and Kastenmeier, Andreas}, title = {Entwicklung und Regelung eines hydraulischen Biegepr{\"u}fstands}, series = {Virtuelle Instrumente in der Praxis 2015 - Begleitband zum 20. VIP-Kongress.}, booktitle = {Virtuelle Instrumente in der Praxis 2015 - Begleitband zum 20. VIP-Kongress.}, editor = {Rahman, Jamal and Heinze, Ronald}, publisher = {VDE-Verlag}, address = {Berlin/Offenbach}, language = {de} } @inproceedings{NueblerSchmidEhrlich, author = {N{\"u}bler, S. and Schmid, Vinzent and Ehrlich, Ingo}, title = {FEM-Simulation of a Tube to Flange Joint under Bending Load}, series = {Applied Research Conference 2016 - ARC 2016, Augsburg, 24 June 2016}, booktitle = {Applied Research Conference 2016 - ARC 2016, Augsburg, 24 June 2016}, editor = {Mottok, J{\"u}rgen and Reichenberger, Marcus and Stolle, Reinhard}, publisher = {Pro Business Verlag}, address = {Berlin}, 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} } @article{RomanoEisenriedJungbaueretal., author = {Romano, Marco and Eisenried, Michael 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 = {Journal of Achievements in Materials and Manufacturing Engineering (JAMME)}, volume = {68}, journal = {Journal of Achievements in Materials and Manufacturing Engineering (JAMME)}, number = {1}, pages = {32 -- 44}, abstract = {Purpose: A prepreg production device in laboratory scale is used to develop the production process of unidirectionally reinforced prepregs. Design/methodology/approach: The aim of the prepreg production device is to impregnate different types of reinforcement fibers with an arbitrarily selectable thermoset matrix system that completely satisfies the requirements for autoclave processing. As the prepreg production device is designed and built up modularly every module corresponds one step in the process. Findings: To identify the parameters of the production process and investigate its sensitivity on the material quality of both the prepreg as an uncured semi-finished product and the composite as the cured material experimental investigations regarding the resin flow, fiber volume content, mass per unit area and void content are carried out. Overall four material combinations have been investigated, where in each case the selected impregnation temperature and the width of the impregnation gap has been reproducibly varied in selected steps. Research limitations/implications: The experimental characterization of the prepregs and of the composite material is carried out according to German standards.}, language = {en} } @article{RomanoEhrlichGebbeken, author = {Romano, Marco and Ehrlich, Ingo and Gebbeken, Norbert}, title = {Parametric characterization of a mesomechanic kinematic caused by ondulation in fabric reinforced composites: analytical and numerical investigations}, series = {Frattura ed Integrit{\`a} Strutturale (Fracture and Structural Integrity)}, volume = {11}, journal = {Frattura ed Integrit{\`a} Strutturale (Fracture and Structural Integrity)}, number = {39}, doi = {10.3221/IGF-ESIS.39.22}, pages = {226 -- 247}, abstract = {A parametric characterization of a mesomechanic kinematic caused by ondulation in fabric reinforced composites is investigated by analytical and numerical investigations. Due to the definition of plain representative sequences of balanced plain-weave fabric reinforced single layers based on sines the variable geometric parameters are the amplitude and the length of the ondulation. The mesomechanic kinematic can be observed in both the analytic model and the FE-analyses. The analytic model yields hyperbolic correlations due to the strongly simplifying presumptions that neglect elasticity. In contrast the FE-analyses yield linear correlations in much smaller amounts due to the consideration of elastic parts, yet distinctly.}, language = {en} } @article{RomanoEhrlich, author = {Romano, Marco and Ehrlich, Ingo}, title = {Classification of damping properties of fabric-reinforced flat beam-like specimens by a degree of ondulation implying a mesomechanic kinematic}, series = {Science and Engineering of Composite Materials}, volume = {31}, journal = {Science and Engineering of Composite Materials}, number = {1}, publisher = {Walter de Gruyter GmbH}, issn = {2191-0359}, doi = {10.1515/secm-2024-0019}, abstract = {In order to determine the influence of the ondulations in fabrics on the damping properties of fiber-reinforced plastics, the structural dynamic properties of fabric- and unidirectionally reinforced plastics are investigated. The free decay behavior of flat beam-like specimens is investigated under fixed-free boundary conditions. As the material damping is consistently higher in fabric-reinforced specimens compared to unidirectionally reinforced ones, a contribution of an additionally acting mesomechanic kinematic in fabric weaves is implied. Based on a degree of ondulation, it is possible to classify the enhancement of the material damping and determine the corresponding energy dissipation. The study provides valuable quantitative relations of the additional damping effect due to the mesomechanic kinematic. Compared to the unidirectionally reinforced material, plain weave enhances the material damping by 37…52\% at ˜OPL=0.0133 , whereas twill weave 2/2 enhances it by 31…40\% at ˜OT2=0.0098 . The consideration of the findings contributes to a deeper understanding of the visco-elastic dynamic behavior of fabric-reinforced plastics and allows further applications in research, development, and industry.}, language = {en} } @article{KastenmeierSchmidEhrlichetal., author = {Kastenmeier, Andreas and Schmid, Vinzent and Ehrlich, Ingo and Petratos, P. and Mourtos, N. and Trafalis, T.}, title = {Specimen Preparation and Material Characterization of Filament Wound GFRP Composite Tubes}, series = {Athens Journal of Technology \& Engineering}, volume = {4}, journal = {Athens Journal of Technology \& Engineering}, number = {3}, pages = {191 -- 205}, abstract = {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.}, language = {en} } @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} } @phdthesis{Romano, author = {Romano, Marco}, title = {Charakterisierung von gewebeverst{\"a}rkten Einzellagen aus kohlenstofffaserverst{\"a}rktem Kunststoff (CFK) mit Hilfe einer mesomechanischen Kinematik sowie strukturdynamischen Versuchen}, publisher = {Shaker}, address = {Aachen}, isbn = {978-3-8440-5177-3}, doi = {10.2370/9783844051773}, pages = {254}, abstract = {Die vorliegende Arbeit behandelt die analytische und numerische Identifikation einer mesomechanischen Kinematik in gewebeverst{\"a}rkten Einzellagen sowie deren Validierung {\"u}ber die Strukturdynamik von flachen stabf{\"o}rmigen Probek{\"o}rpern aus kohlenstofffaserverst{\"a}rktem Kunststoff (CFK). Unter der Voraussetzung, dass das wiederholte Wirken der Kinematik Energie dissipiert, tr{\"a}gt sie bei zyklischer viskoelastischer Deformation zus{\"a}tzlich zur reinen viskoelastischen Werkstoffd{\"a}mpfung in gewebeverst{\"a}rkten Einzellagen bei. Die analytischen und numerischen Untersuchungen beschr{\"a}nken sich auf die Betrachtung des ebenen, zweidimensionalen Zusammenhangs einer vollst{\"a}ndigen Ondulation bzw. einer repr{\"a}sentativen Sequenz in Dickenrichtung. Zur Parameteridentifikation werden die geometrischen Abmessungen in definierten Schritten variiert. Daf{\"u}r wird der Grad der Ondulation in gewebeverst{\"a}rkten Einzellagen {\~O}=A/L als dimensionslose Kennzahl eingef{\"u}hrt. Zur Validierung der d{\"a}mpfungserh{\"o}henden Wirkung der in den analytischen und numerischen Untersuchung identifizierten mesomechanischen Kinematik in gewebeverst{\"a}rkten Einzellagen werden in experimentellen strukturdynamischen Untersuchungen frei abklingende Transversalschwingungen von einseitig fest eingespannten Probek{\"o}rpern untersucht. Im Detail werden flache stabf{\"o}rmige Probek{\"o}rper aus kohlenstofffaserverst{\"a}rktem Epoxidharz mit Lagenaufbauten aus 0°-unidirektionalen und gewebeverst{\"a}rkten Einzellagen untersucht. Die Ergebnisse der experimentellen strukturdynamischen Untersuchungen dienen schließlich der Validierung des analytischen Modells und der numerischen Berechnungen. Die d{\"a}mpfungserh{\"o}hende Wirkung der identifizierten mesomechanischen Kinematik wird schließlich in Abh{\"a}ngigkeit des eingef{\"u}hrten Grades der Ondulation {\~O} quantifiziert.}, language = {de} } @article{BohmannSchlampEhrlich, author = {Bohmann, T. and Schlamp, Matthias and Ehrlich, Ingo}, title = {Acoustic emission of material damages in glass fibre-reinforced plastics}, series = {Composites Part B: Engineering}, volume = {155}, journal = {Composites Part B: Engineering}, number = {December}, publisher = {Elsevier}, doi = {10.1016/j.compositesb.2018.09.018}, pages = {444 -- 451}, abstract = {The aim of this study is to compare two different standardized testing procedures, tensile testing and Mode-I double cantilever beam (DCB) testing, to evaluate a possible correlation between the dominant failure in glass fibre-reinforced plastics and their according acoustic emissions (AE). AE is processed by using a burst collection of all recorded transient signals and is further analysed with the k-means clustering algorithm. To generate damage related AE, a series of experiments for tensile testing and Mode-I DCB testing is performed on 16-layer glass fibre/epoxy specimens with a cross-ply lay-up for tensile and an unidirectional lay-up for Mode-I DCB testing. Three sensors at tensile testing and one sensor at Mode-I DCB testing gather AE data. The results of clustered burst signals show a good accordance between both testing procedures, with a similar weighted peak frequency (WPF) range in each classified cluster. In total, three different clusters are determined. An assignment of these three clusters to the three dominant damage mechanisms, visually observed by microscopy, is suggested.}, language = {en} } @techreport{ValentinoRomanoEhrlichetal., author = {Valentino, Piergiorgio and Romano, Marco and Ehrlich, Ingo and Furgiuele, Franco and Gebbeken, Norbert}, title = {Mechanische Charakterisierung von basaltfaser-verst{\"a}rkten Kunststoffen mit Gewebeverst{\"a}rkung - Numerische und experimentelle Untersuchungen}, series = {Forschungsbericht 2013}, journal = {Forschungsbericht 2013}, publisher = {inixmedia GmbH Marketing \& Medienberatung}, organization = {Ostbayerische Technische Hochschule Regensburg}, language = {de} } @inproceedings{Afanasev, author = {Afanasev, Anna}, title = {Force-oriented 3D printing of continuous fiber-reinforced plastic structures}, series = {Applied Research Conference 2019 - ARC 2019, 08 July 2019, Regensburg}, booktitle = {Applied Research Conference 2019 - ARC 2019, 08 July 2019, Regensburg}, editor = {Mottok, J{\"u}rgen and Reichenberger, Marcus}, publisher = {Pro Business GmbH}, address = {Berlin}, isbn = {978-3-96409-182-6}, pages = {213 -- 218}, subject = {Faserverbundwerkstoff}, 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} } @inproceedings{BaumerKastenmeierEhrlich, author = {Baumer, A. and Kastenmeier, Andreas and Ehrlich, Ingo}, title = {A Numerical Study of Reinforced Bolted Composite Joints}, series = {Applied Research Conference 2015: ARC 2015 - N{\"u}rnberg, 3rd July 2015}, booktitle = {Applied Research Conference 2015: ARC 2015 - N{\"u}rnberg, 3rd July 2015}, editor = {Mottok, J{\"u}rgen and Reichenberger, Marcus and Scharfenberg, J. and Ziemann, Olaf}, publisher = {Book-on-demand-Verlag}, pages = {278 -- 282}, language = {en} } @inproceedings{WaetzigSchmidEhrlich, author = {W{\"a}tzig, A. and Schmid, Vinzent and Ehrlich, Ingo}, title = {Damage Modelling of Adhesive Joints Using the Cohesive Zone Model}, series = {Applied Research Conference 2016 - ARC 2016, Augsburg, 24 June 2016}, booktitle = {Applied Research Conference 2016 - ARC 2016, Augsburg, 24 June 2016}, editor = {Mottok, J{\"u}rgen and Reichenberger, Marcus and Stolle, Reinhard}, publisher = {Pro Business Verlag}, address = {Berlin}, language = {en} } @inproceedings{DinnebierEhrlich, author = {Dinnebier, Heinrich and Ehrlich, Ingo}, title = {The Effects of Severe Temperature Changes and High Humidity on Porous CFRP}, series = {Proceedings of the 15th International Materials Symposium (IMSP´2014), Pamukkale University (Denizli, Turkey), 15./17. October 2014}, booktitle = {Proceedings of the 15th International Materials Symposium (IMSP´2014), Pamukkale University (Denizli, Turkey), 15./17. October 2014}, editor = {Meran, C.}, pages = {433 -- 440}, abstract = {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.}, language = {en} } @inproceedings{EhrlichDinnebierJost, author = {Ehrlich, Ingo and Dinnebier, Heinrich and Jost, C.}, title = {Comparison of Impact Delaminations in CFRP Using Ultrasonic Testing, Microfocus Computed X-Ray Tomography and Micrographic Cross-Section}, 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}, editor = {Meran, C.}, pages = {441 -- 450}, language = {en} } @inproceedings{Wenzl, author = {Wenzl, C.}, title = {Comparison of Analytical and Numerical Results for the Deformation of Circular Curved Structures under Pressure Load}, series = {Applied Research Conference 2018 - ARC 2018, 10 July 2018 Deggendorf}, booktitle = {Applied Research Conference 2018 - ARC 2018, 10 July 2018 Deggendorf}, editor = {Mottok, J{\"u}rgen and Reichenberger, Marcus and Bogner, Werner}, publisher = {Pro Business GmbH}, address = {Berlin}, isbn = {978-3-96409-018-8}, pages = {150 -- 155}, language = {en} }