@article{BodeEhrlich, author = {Bode, J. and Ehrlich, Ingo}, title = {Entwicklung eines finiten Elements f{\"u}r Sandwichanwendungen}, series = {Zeitschrift f{\"u}r Angewandte Mathematik und Mechanik (ZAMM), Journal of Applied Mathematics and Mechanics}, volume = {77}, journal = {Zeitschrift f{\"u}r Angewandte Mathematik und Mechanik (ZAMM), Journal of Applied Mathematics and Mechanics}, number = {1}, pages = {41 -- 42}, language = {de} } @article{RomanoHoinkesEhrlichetal., author = {Romano, Marco and Hoinkes, Carl J. J. and Ehrlich, Ingo and H{\"o}cherl, Johannes and Gebbeken, Norbert}, title = {Experimental investigation of energy dissipation properties of fibre reinforced plastics with hybrid layups under high-velocity impact loads}, series = {Journal of Achievements in Materials and Manufacturing Engineering (JAMME)}, volume = {64}, journal = {Journal of Achievements in Materials and Manufacturing Engineering (JAMME)}, number = {1}, pages = {14 -- 20}, abstract = {Purpose: The present work deals with the experimental investigation concerning the energy dissipation capacity of different kinds of reinforcement fibres in monolithic and hybrid layups under high velocity impact loads. The investigated kinds of fibres are carbon, glass and basalt. Design/methodology/approach: The test panels have been impregnated with thermoset resin. Curing was done by autoclave processing. In order to obtain comparable fibre volume contents of approx. 60 \% in the different layups (monolithic and hybrid without and with separating layer), curing cycles adapted to the type of layup have been identified. The resulting fibre volume content of the test panels has been determined both by weighing and experimentally by chemical extraction and calcination. The impact load was applied by an instrumented experimental setup. Thereby both commercially available bullets and bearing balls accelerated with weighted propellant in a sabot have been used as impactors. The measured values are the velocities of the bearing balls as the impactor before and after penetration of the test panels. Findings: In both cases the results show the energy dissipation capacity of each single kind of fibre in case of the monolithic layups as well as the enhanced properties of the hybrid stacked layups without and with the separating layer as a core material. Typical failure modes on the impact surface and on the outlet areas are identified. Research limitations/implications: The influence of the respective kind of impactors, namely bullets and bearing balls, on the evaluated results is identified. Thereby the bearing balls exhibited a higher degree of reproducibility due to several reasons. Originality/value: Fibre reinforced plastics with hybrid stacking sequences can be used as load-bearing structures and at the same time as safety structures for passengers in automotive or aerospace applications. Moreover, with the hybrid stacked composites lightweight concepts can efficiently be realized regarding energy saving issues.}, language = {en} } @article{SieglEhrlich, author = {Siegl, Marco and Ehrlich, Ingo}, title = {Transformation of the Mechanical Properties of Fiber-Reinforced Plastic Tubes from the Cartesian Coordinate System into the Cylindrical Coordinate System for the Application of Bending Models}, series = {Athens Journal of Technology \& Engineering}, volume = {4}, journal = {Athens Journal of Technology \& Engineering}, number = {1}, pages = {47 -- 62}, abstract = {Fiber-reinforced plastic (FRP) tubes are used in many different industries, such as electrical engineering and pipeline construction. The tubes are frequently subjected to bending loads, depending on the application. In order that the dimensioning of the tubes can be ensured, analytical bending models are used to calculate the resulting stresses, strains and displacements in the individual layers of the laminate. This enables the making of a statement about the failure of the fiber-reinforced tube by choosing an appropriate failure criterion. For the use of these bending models, it is necessary to understand the respective underlying theory. The theory provides the basis for the mathematical description of the mechanical properties for a single-layered tube and using the relationships between the stresses and strains that occur in the Cylindrical coordinate system for this calculation step. For this reason, a redefinition of the compliance matrix from the transformation about the winding angle to the Cylindrical coordinate system and a modification of the stress and strain vectors is necessary, because the defined Cartesian coordinate system of the model cannot be used for wounded FRP tubes. The transformation causes an exchange of entries in the compliance matrix, which remain in the correct relationship between the particular stress and strains. This step is not specified and may lead to incorrect results due to the incorrect entry of compliances. The present publication refers to sketch on this issue and represent a simplification of the changeover to the level required by the bending models notation of vectors in the form of a permutation. In addition, a new name for the pre-acquisition of the redefined compliances is given to prevent confusion when entering the material law of a bending model. Finally, the permuted and redefined compliances are proved in an example to determine their accuracy.}, language = {en} } @article{RomanoEhrlichGebbeken, author = {Romano, Marco and Ehrlich, Ingo and Gebbeken, Norbert}, title = {Parametric characterization of a mesomechanic kinematic in plain and twill weave 2/2 reinforced composites by FE-calculations}, series = {Archives of Materials Science and Engineering (ArchivesMSE)}, volume = {97}, journal = {Archives of Materials Science and Engineering (ArchivesMSE)}, number = {1-2}, publisher = {Index Copernicus}, issn = {1897-2764}, doi = {10.5604/01.3001.0013.2869}, pages = {20 -- 38}, abstract = {Purpose: A parametric characterization of a mesomechanic kinematic caused by ondulation in fabric reinforced composites is investigated by numerical investigations. Design/methodology/approach: Due to the definition of plain representative sequences of balanced plain-weave and twill-weave 2/2 fabric reinforced single layers based on sines the variable geometric parameters are the amplitude and the length of the ondulation. Findings: The mesomechanic kinematic can be observed in the FE analyses for both kinds of fabric constructions. Research limitations/implications: The FE analyses consider elasticity and contraction due to Poisson effects, respectively, of the model under selected longitudinal strains. Practical implications: The results are evaluated at relevant positions on the centre-line of the ondulated warp-yarn of the plain representative model. A direct and linear coupling in case of the transversal kinematic behaviour, and thereby a corresponding definite reduction of the evaluated longitudinal strains in terms of the difference of the applied and determined longitudinal strains is identified. Originality/value: Both characteristic purely kinematic reactions due to geometric constraints directly depend on the introduced degree of ondulation. This non-dimensional parameter relates amplitude and length of one complete ondulation, and thus represents the intensity of the ondulation of the respective fabric construction.}, language = {en} } @article{RomanoEhrlichGebbeken, author = {Romano, Marco and Ehrlich, Ingo and Gebbeken, Norbert}, title = {Structural mechanic material damping in fabric reinforced composites}, series = {Archives of Materials Science and Engineering (ArchivesMSE)}, volume = {88}, journal = {Archives of Materials Science and Engineering (ArchivesMSE)}, number = {1}, doi = {10.5604/01.3001.0010.7747}, pages = {12 -- 41}, abstract = {Purpose: A review regarding the acting mechanisms of structural dynamic material damping in fabric reinforced composites is presented. Design/methodology/approach: Mechanical acting principles identified by different investigations are considered. Aspects of the determination and calculation of structural mechanical material properties of fabric reinforced composites are described. Approaches intending the description and classification of ondulations in fabrics reinforced single layers are demonstrated. Findings: The mesomechanic geometry of fabrics is not considered sufficiently by relatively simple homogenization approaches. Yet, it significantly affects its structural dynamic material properties, especially the dynamic ones. Research limitations/implications: In each case the different damping mechanisms act coupled and occur at the same time. Therefore a separation procedure is required in any case. Practical implications: Against the background of the comparison and remarks of the presented papers a reasonable further procedure is recommended. Thereby, FE-calculations with a parametrical variation of the mesomechanic geometry in order to identify kinematic correlations due to geometric constraints are suggested. Originality/value: The idea of the representation of the geometric conditions in terms of a degree of ondulation is described. Such a non-dimensional specific value representing the intensity of the ondulation would enable the comparability of the results of different kinds of investigations.}, language = {en} } @article{ValentinoSgambitterraFurgiueleetal., author = {Valentino, Piergiorgio and Sgambitterra, Emanuele and Furgiuele, Franco and Romano, Marco and Ehrlich, Ingo and Gebbeken, Norbert}, title = {Mechanical characterization of basalt woven fabric composites}, series = {Frattura ed Integrit{\`a} Strutturale (Fracture and Structural Integrity)}, volume = {8}, journal = {Frattura ed Integrit{\`a} Strutturale (Fracture and Structural Integrity)}, number = {28}, doi = {10.3221/IGF-ESIS.28.01}, pages = {1 -- 11}, abstract = {Basalt fabric composite, with different twill wave reinforcements, i.e. twill 2/2 and twill 1/3, have been studied in this work by means of experimental tests and numerical finite element (FE) simulations. As fabric reinforcements show repeating undulations of warp and fill yarn, simple mixtures law cannot be applied. As a consequence, the mesoscopic scale, lying between the microscopic and the macroscopic one, has to be taken into account to mechanically characterize a fabric reinforced composite. The aim of this work is to evaluate the stiffness of a fabric reinforced composite in warp and fill direction. In particular a numerical FE model, assuming elliptical sections and sinusoidal shape of the yarns, has been implemented and experimental tests have been carried out in order to validate the proposed model. Finally, the strength and the failure modes le orientation, have been experimentally investigated.}, language = {en} } @techreport{SchlampEhrlich, author = {Schlamp, Matthias and Ehrlich, Ingo}, title = {Analyse des Impact-Verhaltens gekr{\"u}mmter Strukturbauteile von Luftfahrzeugen zur Entwicklung eines Struktur{\"u}berwachungssystems f{\"u}r faserverst{\"a}rkte Kunststoffe - BIRD}, series = {Forschung 2019 / Ostbayerische Technische Hochschule Regensburg}, journal = {Forschung 2019 / Ostbayerische Technische Hochschule Regensburg}, editor = {Baier, Wolfgang}, publisher = {VMK Verlag f{\"u}r Marketing \& Kommunikation GmbH \& Co. KG}, organization = {Ostbayerische Technische Hochschule Regensburg}, isbn = {978-3-9818209-6-6}, pages = {40 -- 41}, abstract = {Die in Flugvorausrichtung weisenden Bauteile von Luftfahrzeugen sind oftmals durch Einschl{\"a}ge aufgrund von Vogelschlag, Hagel oder aufgewirbelten Kleinteilen gef{\"a}hrdet. Diese Einschl{\"a}ge, sogenannte Impacts, weisen bei faserverst{\"a}rkten Kunststoffen ein stark kr{\"u}mmungs- und materialabh{\"a}ngiges Verhalten und Schadensausmaß auf. Impact-Sch{\"a}digungen f{\"u}hren oftmals zu hohen Reparaturkosten, welche durch eine genauere Kenntnis des Schadens verringert werden k{\"o}nnen. Zur Klassifizierung dieser Sch{\"a}digungen steht dabei vor allem das auftretende Frequenz signal des Impacts im Fokus der Untersuchungen.}, language = {de} } @article{RomanoHoinkesEhrlichetal., author = {Romano, Marco and Hoinkes, Carl J. J. and Ehrlich, Ingo and H{\"o}cherl, Johannes and Gebbeken, Norbert}, title = {Experimental investigation of fibre reinforced plastics with hybrid layups under high-velocity impact loads}, series = {Frattura ed Integrit{\`a} Strutturale (Fracture and Structural Integrity)}, volume = {8}, journal = {Frattura ed Integrit{\`a} Strutturale (Fracture and Structural Integrity)}, number = {29}, doi = {10.3221/IGF-ESIS.29.34}, pages = {384 -- 398}, abstract = {This paper deals with experimental investigations concerning energy dissipation capacity of different kinds of reinforcement fibres in monolithic and hybrid layups under high-velocity impact loads. The investigated kinds of fibres are carbon, glass and basalt fibres. Therefore test panels, using the same thermoset resin, were built up and cured by autoclave processing. The fibre volume content of the test panels has been determined. Furthermore the influence of a separating layer at selected positions in the hybrid stacked panels was investigated. The results show the influence and the energy dissipation capacity of each single kind of fibre and the enhanced properties for the hybrid layups by hybrid stacking sequences and the use of a separating core material.}, language = {en} } @techreport{PutzerRasmussenEhrlichetal., author = {Putzer, Michael and Rasmussen, John and Ehrlich, Ingo and Gebbeken, Norbert and Dendorfer, Sebastian}, title = {Muskuloskelettale Simulation zur Untersuchung des Einflusses geometrischer Parameter der Wirbelk{\"o}rper auf die Belastung der Lendenwirbels{\"a}ule}, series = {Forschungsbericht 2013 / Ostbayerische Technische Hochschule Regensburg}, journal = {Forschungsbericht 2013 / Ostbayerische Technische Hochschule Regensburg}, editor = {Baier, Wolfgang}, address = {Regensburg}, organization = {Ostbayerische Technische Hochschule Regensburg}, pages = {60 -- 61}, language = {de} } @article{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 reinforced plastics by the free decay method}, series = {Journal of Achievements in Materials and Manufacturing Engineering}, volume = {63}, journal = {Journal of Achievements in Materials and Manufacturing Engineering}, number = {2}, pages = {65 -- 80}, abstract = {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.}, language = {en} } @techreport{SieglEhrlich, author = {Siegl, Marco and Ehrlich, Ingo}, title = {Internationale Forschung zum Biege- und Deformationsverhalten von faserverst{\"a}rkten Kunststoffrohren}, series = {Forschung 2019 / OTH Regensburg}, journal = {Forschung 2019 / OTH Regensburg}, editor = {Baier, Wolfgang}, publisher = {VMK Verlag f{\"u}r Marketing \& Kommunikation}, organization = {Ostbayerische Technische Hochschule Regensburg}, isbn = {978-3-9818209-6-6}, pages = {42 -- 43}, language = {de} } @article{BartschBehamGebhardtetal., author = {Bartsch, Alexander and Beham, Daniela and Gebhardt, Jakob and Ehrlich, Ingo and Schratzenstaller, Thomas and Monkman, Gareth J.}, title = {Mechanical Properties of NdPrFeB Based Magnetoactive Bisphenol-Free Boron-Silicate Polymers}, series = {Journal of Nanomedicine and Nanotechnology}, volume = {14}, journal = {Journal of Nanomedicine and Nanotechnology}, number = {6}, publisher = {Walsh Medical Media}, issn = {2157-7439}, doi = {10.35248/2157-7439.23.14.705}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-67425}, abstract = {Following a ban on many materials containing bisphenol-A, new bisphenol-free Boron silicates have been found as substitutes. The purpose of this study is to describe the mechanical properties of these bisphenol-free magnetoactive borosilicate polymers containing hard magnetic particles. Samples of 0\%, 33\% and 66\% by wt. were loaded for compression using a universal testing machine. The maximum forces occurring for different travel speeds were compared before and after post-magnetization treatments. The post-magnetization included 2 stages. In addition, the change in mechanical properties within 24 hours after the post-magnetization process was investigated. Furthermore, the influence of speed and particle content were investigated. In general, there is a correlation between the required compressive force and, the level of post-magnetization stress, the increase in travel speed and particle content in the boron silicate. Comparison of the non-post-magnetized and post-magnetized samples using two-tailed t-tests shows that the p-values for all weight fraction changes in NdPrFeB particles and travel speeds are less than 0.001. Also, a comparison between tests in which the traverse speed was varied also showed significant changes in the resulting compression forces. The same is valid for changes in the weight ratio of the NdPrFeB particles in the samples. For post-magnetized samples, no significant difference can be observed in the first 24 hours following magnetization. In summary, the material presents viscoelastic, plastic force-displacement behavior, which can be well recognized by its bi-linear curve shape. The investigation shows that borosilicate polymers based on NdPrFeB can have their mechanical behavior modified and controlled by post-magnetization processes. This opens new possibilities for many future applications.}, language = {en} } @inproceedings{JudenmannHoltmannspoetterEhrlich, author = {Judenmann, Anna and Holtmannsp{\"o}tter, Jens and Ehrlich, Ingo}, title = {Additive Manufacturing of Continuous Fiber-Reinforced Composites}, series = {Proceedings of the Munich Symposium on Lightweight Design 2022}, booktitle = {Proceedings of the Munich Symposium on Lightweight Design 2022}, language = {de} }