On modern vehicles, the demand is made to be in every respect as efficient as possible. A technical method to increase energetic efficiency is to reduce the vehicle mass through the implementation of lightweight construction measures. The energy consumption decreases by that and the vehicle dynamics behavior of conventionally and alternatively respectively electrically powered vehicles increases. In the department Lightweight and Hybrid Design Methods of the Institute of Vehicle Concepts in Stuttgart in collaboration with 3A Composite Core Materials, a method which allows to realize sandwich structures for automotive structural applications analytically and conceptually, is developed. The development method based on material and component testing and material values would be determined at different loads, for example in pressure and in-plane tests. These values are transmitted into the analytical determination of so called failure mode maps to derive appropriate sandwich structures. With novel sandwich structures the objectives of high structural stiffness and strength are tracked, as well as a high level of energy absorption potential. By function integrating the potential of lightweight construction, depending on the energy absorption per structural weight, can be further increased. Accompanying tests on generic structures are made to validate the failure behavior. Also the influence of core material on the deformation behavior is examined. The results from the tests are transferred to a vehicle front structure of a planned lightweight vehicle of class L7E called "Safe Light Regional Vehicle" (SLRV). The behavior of the structure is examined in static and dynamic tests. The energy absorbing capacity can be further increased by geometric optimization and the use of different core materials. The research on sandwich materials is part of the research project Next Generation Car (NGC) of the DLR and represents in terms of the new vehicle concept SLRV in sandwich design a novel vehicle concept of this joint project.
This study proposes a hybrid structural design concept of polyurethane foam-filled magnesium alloy AZ31B rectangular thin-walled beams which serve as energy absorbing components in automotive applications. Uniaxial tensile and compressive tests, and fracture tests were performed to investigate the material mechanical properties. Dynamic three-point bending tests were performed to study the deformation/fracture modes and energy absorption capacity for the foamfilled AZ31B beams, and to compare these mechanical properties with those for mild steel DC04 beams. Different AZ31B beams were filled with a variation of foam density (0.05, 0.20 and 0.30 g/ cm 3 ). It was found that the AZ31B beam filled with 0.20 g/cm 3 foam reached the highest specific energy absorption; moreover, it absorbed more energy and reached much higher specific energy absorption than the foam-filled DC04 beam filled with the same foam, although the former one was nearly 54% lighter. The potential advantage of the foam-filled AZ31B beams is possibly associated with the high work hardening rate of AZ31B sheet in compression, which may involve more material in plastic deformation compared with the foam-filled DC04 beams. It has therefore been demonstrated that the hybrid structural design concept of the polyurethane foam-filled AZ31B beam has potential applications in auto-body structures.
Quasi-static/dynamic three-point bending tests were conducted to assess the crash performance of magnesium alloy AZ31B extruded and sheet tubes at the German Aerospace Centre (DLR) – Institute of Vehicle Concepts in Stuttgart. Different foam-filled AZ31B beams with a variation of foam density and thickness were fabricated through several manufacturing processes: cold bending, tungsten inert gas welding, cathodic dip painting and polyurethane foam injection. The experimental results were compared with those from mild steel DC04 tubes. It shows that empty magnesium alloy AZ31B outperforms steel DC04 in terms of specific energy absorption for the empty tubes with equivalent volume when subjected to bending loads. It was found that the foam-filled tubes achieved much higher load carrying capacity and specific energy absorption than the empty tubes. Moreover, there is a tendency showing that a foam-filled beam with a higher foam density reaches higher load carrying capacity, but fractures earlier. The foam-filled AZ31B tube with 0.20 g/cm3foam obtained the highest specific energy absorption, but this outperformance was weakened due to the earlier fracture. In addition, the numerical simulation utilising material model MAT_124 in LS-DYNA explicit FEA package was performed. The simulation results indicate that using calibrated stress-strain curves and failure parameters, material model MAT_124 yields a general good agreement with the experimental results.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.