Finite Element Modeling of the Frame for Body on Frame Vehicles, Part 1 - Subsystem Investigation

For a body-on-frame (BOF) vehicle, the frame is the major structural subsystem to absorb the impact energy in a frontal vehicle impact. It is also a major contributor to energy absorption in rear impact events as well. Thus, the accuracy of the finite element frame model has significant influence on the quality of the BOF vehicle impact predictability. This study presents the latest development of the frame modeling methodology on the simulation of BOF vehicle impact performance. The development is divided into subsystem (frame sled test) and full system (full vehicle test). This paper presents the first phase, subsystem testing and modeling, of the frame modeling development. Based on the major deformation modes in frontal impact, the frame is cut into several sections and put on the sled to conduct various tests. The success of the sled test highly depends on whether the sled results can replicate the deformation modes in the full vehicle. For each section, the sled runs at various speeds to explore the full spectrum of the frame's response. CAE models are created to correlate to the test results. These results can then be used to create a full vehicle frame model, which will be discussed in part two[1]. Through CAE model correlation, we have identified three major factors to improve the accuracy of the model; the strain rate, the forming effect and the welding effect. The comparison of the CAE prediction and correlation with the sled test results are discussed in this paper.