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Vehicle body structure designs include finite element analyses and vehicle physical tests providing information to confirm the analytical simulations results. Contemporary finite element (FE) software comprises FEs (referred as analytical FEs) developments based on assumptions and hypotheses which might require experimental confirmation both of analyses results and sufficiency of selected analytical FEs. Experimental FEs presented in this paper provide the capabilities of more objective analytical simulation results confirmations. Experimental FEs are developed based on Structural Mechanics and Mathematical Statistics theories and on the experience of special strain gages sets usage during implementations of the Thin-Walled Beam theory in automotive vehicle structure analyses implementations.

This paper is a continuation of SAE Paper 2006-01-1227 “Three-Dimensional FEM Beam Elements”, which describes development of the elements static linear mathematical formulations based on Thin-Walled Beam theory, which is in reality Thin-Walled Cylindrical Shell theory. Applications of the thin-walled open and closed cross sections elements developed in Paper 2006-01-1227, both in linear and nonlinear/crash simulations, are the focus of this paper. Those elements are considered more correctly refer to as cylindrical shell instead of beam elements. The computational efficiency advantages of using cylindrical shell instead of or with plane shell elements are described and illustrated in this paper.

Finite Element Method's (FEM) beam elements are so far one-dimensional and mostly based on hypotheses of rigid and plane (not warping) cross sections. The advantages of those elements are their computational efficiency and their formulation based on the Strength of Materials theory. There are limitations, however, of using such elements (even with accounting for cross section's warping) along with multi-dimensional FEM elements in contemporary complex three-dimensional structures' FE models. This paper presents new developments, which objective is to have all kinds of three-dimensional FEM beam elements (solid and thin-walled) with variable number (as needed) of nodal points and degrees of freedoms and being capable of working with all kinds of FEM elements in three-dimensional structures FEM models, while still having the advantage of one-dimensional beam elements computational efficiency.

Side impact dummy (SID) is a human-like test device used in the National Highway Transportation Safety Administration (NHTSA) mandated side impact test of vehicles sold in the USA. A finite element model of SID has been developed at GM as a part of a project to simulate the side impact test. The objective is to better predict physical test results by replacing traditional rigid-body lumped parameter models with a finite element model. The project included, besides mesh generation, the development of new LS-DYNA3D constitutive models for rubber and foam-like materials, and enhancements of contact interface and other algorithms. This paper describes the GM SID finite element model and its performance in side impact test simulations.

Advanced Bus Remanufacturing (ABR) is the concept whereby a new body from an Advanced Design Bus is installed on the chassis from a “New Look” bus. This process provides a property the option of updating its fleet of buses at approximately two-thirds the cost of buying new. Testing is required to insure that the combination of the two different structures into the ABR will not shorten the expected service life. A special testing program, designed to reduce the need for expensive and time-consuming endurance testing, is discussed. The three types of tests in this program, static, vibration, and endurance, are described. Two prototype ABR buses are currently undergoing testing. Sample results from the static and vibration tests in this program are presented and discussed.

CAR/BUS BODIES, truck cabs or truck/trailer frames in their mathematical representation are considered as shell-type or combined shell-and-beam type structures. Vlasov's Theory of Thin-Walled Beams turns out to be a fruitful means of analyzing these structures for strength and cost effectiveness. The use of this theory in the finite element method and in overall vehicle structural analyses is shown. With the application of this theory, these analyses become more comprehensive and explicit. Typical vehicle structures are analyzed. Critical load/stress areas are identified and evaluated.