Evaluation on spot weld models in structural dynamic analysis of automotive body in white

Spot weld models are widely used in finite element analysis(FEA) of automotive body in white(BIW) to predict static, dynamic, durability and other characteristics of automotive BIW. However, few researches are done on evaluation of the validity of these spot weld models in structural dynamic analysis of BIW. To evaluate the validity and accuracy of spot weld models in structural dynamic analysis of BIW, two object functions, error function and deviation function, are introduced innovatively. Modal analysis of Two-panel and Double-hat structures, which are the dominated structures in BIW, is conducted, and the values of these two object functions are obtained. Based on the values of object functions, the validity of these spot weld models are evaluated. It is found that the area contact method(ACM2) and weld element connection(CWELD) can give more precise prediction in modal analysis of these two classical structures, thus are more applicable to structural dynamic analysis of automotive BIW. Modal analysis of a classical BIW is performed, which further confirms this evaluation. The error function and deviation function proposed in this research can give guidance on the adaptability of spot weld models in structural dynamic analysis of BIW. And this evaluation method can also be adopted in evaluation of other finite element models in static, dynamic and other kinds of analysis for automotive structures.