Advanced Vehicle Body Concept Modeling Approach Using Reduced Models of Beams and Joints

The paper presents a vehicle body concept modeling methodology based on reduced models of beams, joints and panels. The aim of the approach is to enable accurate Noise, Vibration and Harshness (NVH) simulations of the vehicle Body in White (BIW) already in the initial phases of the vehicle design process, when the detailed geometry information has not yet become available. In the presented approach, concept models of beams and joints are created, respectively, by means of a geometric analysis of beam-member cross-sections and a static analysis of joints FE models that results in an efficient matrix formulation. Concept panels are modeled by coarsening the original FE mesh. Improvements to the approach are proposed through the introduction of a new connection element, so-called “RBE2.5”, which permits to refine the modeling of shell-based beam and joint ends, leading to more accurate joint matrix formulation. Furthermore, a new optimization process has been worked out, which allows taking into account the discontinuities of the original beam-like structure sections.. The proposed approach has been validated by using an industrial case study, for which the beam, joint and panel concept methodology has been used in combination with a substructuring technique to create an efficient and accurate vehicle BIW model. More specifically, simplified models of beams, joints and panels of the upper region of the vehicle BIW are created, while the bottom part has been reduced by means of MacNeal‟s Method.