TY - GEN A1 - Judenmann, Anna A1 - Pongratz, Christian A1 - Ehrlich, Ingo A1 - Höfer, Philipp A1 - Holtmannspötter, Jens T1 - Additive Fertigung von endlosfaserverstärkten Kunststoffstrukturen T2 - Münchner Leichtbauseminar 2022, 26. October 2022, 16. November 2022, 30 November 2022, Munich/Neubiberg/Garching N2 - Additive Fertigung hat sich in zahlreichen industriellen Anwendungen etabliert und bildet eine wichtige Schlüsseltechnologie. Im Gegensatz zu metallischen Werkstoffen, haben additiv gefertigte Bauteile aus Kunststoffen geringere Festigkeit und Steifigkeit, sodass sich ihre Verwendung als lasttragende Strukturen schwierig gestaltet. Insbesondere der Einsatz von endlosen Verstärkungsfasern kann die mechanischen Eigenschaften additiv gefertigter Strukturen signifikant verbessern und die Fertigung hochbelastbarer Faserverbundstrukturen im 3D-Druckverfahren ermöglichen. Daher gilt es aktuell notwendige Anlagen und Prozessketten für den Fertigungsprozess aber auch Vorgehensweisen für die belastungsoptimierte Auslegung der Faserverläufe innerhalb des Bauteils zu entwickeln, um so das Themengebiet „Endlosfaserverstärkter 3D-Druck“ weiter voranzutreiben. Für mehr räumliche Freiheit bei der Positionierung der Druckbahnen können industrieroboterbasierte Systeme eingesetzt werden, um so das Potenzial gerichteter Bauweise von Faserverbundstrukturen auch im additiven Fertigungsprozess vollumfänglich ausschöpfen zu können. Dabei ermöglicht ihr Einsatz auch eine räumliche Ablage der Faserverstärkung, wobei für die Materialablage ein geeigneter 3D-Druckkopf erforderlich ist. Für die Implementierung der Faserverstärkung ist zudem eine dem Lastfall entsprechende Auslegung des Bauteils sowie die Ermittlung einer sinnvollen Faserpositionierung innerhalb des Bauteils erforderlich, wobei unterschiedliche Variablen aus den Bereichen Material, Struktur und Fertigungsprozess berücksichtigt werden müssen. Im Rahmen des Vortrages werden die Herausforderungen der Technologieentwicklung des endlosfaserverstärkten 3D-Drucks aufgegriffen sowie auf eine belastungsorientierte Faserpositionierung näher eingegangen. Aktuelle Erkenntnisse werden diskutiert sowie eine Entwurfsmethodik für die Prozesspfadgenerierung vorgeschlagen. KW - additive manufacturing KW - continuous fiber KW - composites KW - toolpath Y1 - 2022 ER - TY - PAT A1 - Olbrich, Florian A1 - Pongratz, Christian A1 - Bierl, Rudolf A1 - Ehrlich, Ingo T1 - Method and System for Evaluating a Structural Integrity of an Aerial Vehicle T2 - Europäisches Patentblatt (09.12.2020) zur Anmeldung: OTH Regensburg, Anmeldenummer: 19179054.2, Patentnummer 1001/3748327, Veröffentlichungsnummer: 3 748 327 Y1 - 2020 SP - 395 EP - 396 ER - TY - JOUR A1 - Niedernhuber, Michal A1 - Holtmannspötter, Jens A1 - Ehrlich, Ingo T1 - Fiber-oriented repair geometries for composite materials JF - Composites, Part B N2 - In this paper, the idea of fiber-oriented repair geometries for carbon fiber reinforced plastics (CFRP) is investigated. It considers the differing mechanical properties of unidirectional fiber reinforced material by excluding overlapping regions perpendicular to the fiber direction of the particular layer. A mechanical and numerical comparison of tensile strength of stepped joints with continuous step lengths per ply and stepped joints with reduced step lengths in plies with fiber orientation differing from load direction is performed. Finite element simulations show similar shear stresses. Mechanical tests of CFRP laminates with stepped joints show no significant deviation in tensile strength, in spite of a joint length reduction of nearly 40%. This leads to the possibility of a significant reduction of repair area. Y1 - 2016 U6 - https://doi.org/10.1016/j.compositesb.2016.03.027 VL - 94 SP - 327 EP - 337 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 - JOUR A1 - Savelev, Dmitrii V. A1 - Glavan, Gašper A1 - Belan, Viktoria O. A1 - Belyaeva, Inna A. A1 - Fetisov, Leonid Y. A1 - Shamonin (Chamonine), Mikhail T1 - Resonant Magnetoelectric Effect at Low Frequencies in Layered Polymeric Cantilevers Containing a Magnetoactive Elastomer JF - Applied Sciences N2 - In this work, the resonance enhancement of magnetoelectric (ME) coupling at the two lowest bending resonance frequencies was investigated in layered cantilever structures comprising a magnetoactive elastomer (MAE) slab and a commercially available piezoelectric polymer multilayer. A cantilever was fixed at one end in the horizontal plane and the magnetic field was applied horizontally. Five composite structures, each containing an MAE layer of different thicknesses from 0.85 to 4 mm, were fabricated. The fundamental bending resonance frequency in the absence of a magnetic field varied between roughly 23 and 55 Hz. It decreased with the increasing thickness of the MAE layer, which was explained by a simple theory. The largest ME voltage coefficient of about 7.85 V/A was measured in a sample where the thickness of the MAE layer was ≈2 mm. A significant increase in the bending resonance frequencies in the applied DC magnetic field of 240 kA/m up to 200% was observed. The results were compared with alternative designs for layered multiferroic structures. Directions for future research were also discussed. KW - flexible composite KW - low frequency KW - magnetoactive elastomer KW - magnetoelectric effect KW - piezoelectric polymer Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-30637 N1 - corresponding authors: Dmitry V. Saveliev and Mikhail Shamonin VL - 12 IS - 4 SP - 1 EP - 13 PB - MPDI ER - TY - JOUR A1 - Gebhardt, Jakob A1 - Schlamp, Matthias A1 - Ehrlich, Ingo A1 - Hiermaier, Stefan T1 - Low-velocity impact behavior of elliptic curved composite structures JF - International Journal of Impact Engineering N2 - Although many composite structures are inconsistently curved, such as the leading edges of aircraft wings, the variety of research in impact engineering is almost limited to the impact performance of plates or cylindrically curved specimens. It is not known whether the findings obtained from standardized tests can be transferred to curved structures or which adaptions are required. Therefore, a deeper understanding of the deformation and damage behavior of inconsistently curved structures is essential to transfer the observed impact behavior of flat specimens to general curved structures and therefore to utilize the full lightweight potential of a load-specific design. An accurate description of the procedure as well as the results of the experimental and numerical study of the low-velocity impact behavior of differently single-curved elliptic specimens is presented. To close the research gap of the impact behavior of geometries with curvatures between the plates and simplified leading edges, novel specimens geometries have been derived from established impact test standards. Glassfiber-reinforced specimens are subjected to an instrumented impact test at constant impact energy. This is numerically investigated by a stacked-layer model, which used cohesive zone modeling to enable the simulation of matrix cracking, fiber fracture and delamination. The resulting projected damage areas, as well as the force and deflection histories, were evaluated and section cuts were examined to discuss the damage morphology, formation and propagation process. Significant effects on maximum deflection, compliance and dynamic behavior on the size and morphology of damage were found. KW - Impact damage KW - Impact behavior KW - Curved composite KW - Numerical model KW - GFRP Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-59304 N1 - Corrsponding author: Jakob Gebhardt VL - 180 PB - Elsevier ER - TY - GEN A1 - Schimmer, Florian A1 - Gebhardt, Jakob A1 - Motsch-Eichmann, N. A1 - Hausmann, Joachim M. A1 - Ehrlich, Ingo T1 - The effect of curvature on the low-velocity impact resistance of CF/PEEK laminates T2 - 30 Years IVW Anniversary Colloquium, Leibnitz-Institut für Verbundwerkstoffe Kaiserslautern, 2021 Y1 - 2021 ER -