Nonlinear Dynamic Simulation of Fuel Tank Strap Stress and Fatigue Life under Proving Ground Conditions

In automotive CAE durability analysis, simulation of dynamic stress and fatigue life of fuel tank straps is a complex problem. Typically a fuel tank is held with fuel tank straps. Its movement lies in the domain of nonlinear large rotation dynamics. Moreover, the sloshing behavior in the fuel tank makes the problem even more intricate.

The objective of this study is to investigate the fuel tank and fuel tank strap movement under proving ground conditions using the nonlinear large rotation dynamic method with RADIOSS, a commercial code. In this study, the stress distribution of the fuel tank strap can be predicted with Arbitrary Lagrange-Euler Method (ALE) to simulate fuel and fuel vapor. A commercial fatigue code, FE-Fatigue, is used to predict the fatigue life of the fuel tank straps. The analyses have accurately predicted the crack initiation sequence and locations in the fuel tank straps, and show good correlation with test. The utilization of this method can give design direction to minimize the iteration of lab testing and expedite the design period.