Showing papers by "Maik Gude published in 2008"

Modular Concepts and the Design of the ModCar Body Shell

Abstract: To achieve the aim of building a car to customer order within 5 days, an innovative modular concept car was conceived that supported the planned costeffective built-to-order proposition and stockless production. In a multi-stage design process the automotive body shell, outer panels and selective outer structures have been developed to fit over the modular body frame, offering numerous advantages. The project had a twin aim of meeting not only the technical requirements, which included not only modularity, safety, low weight and a panoramic view, but also the emotional design aspects, including looking “sporty” and “agile”. The appearance of the car body shell for the ModCar is of great importance if it is to be commercially viable and achieve success in the marketplace. Developments in lightweight materials and process technologies enabled the development of advanced function-integrated lightweight vehicle modules for series manufacture. The ModCar fulfils the criteria regarding passenger protection with respect to the Euro-NCAP standards. In addition, simulations show that the essential bending stiffness has been achieved. An optimised lightweight door module consisting of novel materials demonstrates good overall performance with regard to static load and crash behaviour testing. As such, the ModCar demonstrates that the novel concepts employed may be used to successfully produce a vehicle that is saleable in the European market.

Numerical and experimental deformation and failure analysis of 3D-textile reinforced lightweight structures under impact loads

Abstract: The load-adapted design of 3D-textile reinforced composites for crash and impact applications requires an assured knowledge of the strain rate dependent deformation and failure behaviour [1]. One of the greatest challenges still facing optimised use of composite materials in impact loaded structures are related to insufficient simulation capabilities, so that nowadays the design of highly dynamically loaded composite structures is characterised by expensive experiments [2]. To overcome these difficulties, for commercial explicit FE codes new material models have been developed in the last years that account for the failure and post-failure behaviour of composite structures under impact loading [3]. The paper deals with the study and verification of a damage model, which has recently been implemented in LS-DYNA for solid elements. Especially, its capabilities to predict the deformation and damage behaviour of complex shaped 3Dtextile reinforced laminate structures under impact loading conditions have been investigated using a textile reinforced bucket structure for bulk goods transportation as an example. The reinforcement structure of the bucket consists of a novel multi-layered flat bed weft knitted textile preform, which has been infiltrated in the RTM process. A drop tower was used for the impact experiments, where the impactor shape, the impact energy as well as the loading direction and the impact location have been varied. The experimental setup (Figure 1) enables the investigation of the real time deformation behaviour from different perspectives (Figure 2b) via two high speed video cameras. Five different impact setups have been investigated in total. Figure 1 Setup of the impact testing rig Figure 2 Comparison of numerical results (a) and experimental real time impact deformations (b) The numerical investigations were focused on the realistic prediction of the impact behaviour in terms of the elastic deformation during the impact (Figure 2) and the post impact damage behaviour (Figure 3). Therefore complex failure models for composites based on the failure criterion of HASHIN [4], the damage model based on MATZENMILLER [5] and an approach for strain rate dependency were applied by the use of *MAT_COMPOSITE_DMG_MSC in LSDYNA. The required input data as strain rate dependent stiffness coefficients and strengths as well as degradation parameters have been determined in highly dynamic tension, compression and shear tests. Figure 3 Comparison of the post impact damage (numerical (a) and experimental results (b, c)) It has been shown that the material model enables a realistic prediction of the experimentally observed impact damage and failure phenomena of complex shaped 3D-reinforced composite structures.