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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 recent surveys of customer satisfaction regarding full size pickup trucks have created new mandates in performance of such vehicles. The customers for this class of vehicles demand new frontiers in attributes such as NVH, ride and handling performance that previously only belonged to the luxury passenger cars. The full size pickup truck in question must retain a tough image and be as durable as the previous generation truck that it replaces. But it also needs to be user friendly in order for one to drive it like an every day passenger car on a daily basis. The challenge is to design for the NVH performance that matches and surpasses many well behaved and “good” NVH passenger cars without any compromise in durability performance. An NVH 7-8 subjective rating performance is targeted for the design of full size pickup truck during vehicle operation.

One of the difficulties in predicting the structural behavior of vehicles such as the full size pickup trucks is the non-linearities involved during the course of the durability events. The current practice in durability and fatigue life prediction of vehicles is to conduct fatigue analysis on the structure using the measured road loads and estimate the fatigue incurred using the in-house and commercially available programs. In this paper the authors attempt to seek a different solution to the durability problem by conducting an upfront non-linear analysis. The results are then compared with the prediction by the fatigue life program in addition to the durability test results obtained on the early prototypes. To conduct the non-linear analysis ABAQUS FEA program is chosen for this investigation and for the linear analysis MSC/NASTRAN is utilized. Subsequently in-house fatigue program is used to predict the fatigue incurred.

Recent surveys of customer satisfaction with full size pickup trucks have raised the standards for passenger comfort and refinement of such vehicles. Customers for this type of vehicle demand performance levels for attributes such as NVH, ride, and handling that previously belonged to luxury passenger cars. Along with the increased passenger comfort, full size pickup trucks must retain a tough image and be as durable as the previous generation trucks. The challenge is to design for NVH performance that can match and surpass many well behaved and “good” NVH passenger cars without any compromise in durability performance. One aspect of “good” NVH is a steering wheel which is free from vibration. As part of the development of a new design for a full sized pick up truck, an NVH subjective rating of 8-9 (10 is maximum) was targeted for the design of steering column/ instrument panel assembly.