Search Results

Since the environment of vehicle operation is dynamic in nature, dynamic methods should be used in vehicle durability analysis. Due to the constraints in current computer resources, simulation of vehicle durability tests and structural fatigue life assessment need special approaches and efficient CAE tools. The purpose of this paper is to present an efficient methodology and a feasible vehicle dynamic durability analysis process. Two examples of structural durability analysis using transient dynamics are given. The examples show that vehicle stress analysis and fatigue life prediction using dynamic method is now feasible by employing the presented method and process.

Automotive product development requires higher degree of quality upfront engineering, faster CAE turn-around, and integration with other functional requirements. Prediction of potential durability concerns using analytical methods for sheet metal structures subjected to road loads and other customer uses has become very important. A process has been developed to provide design direction based upon peak loads, simultaneous peak loads, and vehicle program analytical or measured loads. It identifies critical loads at each input location and load sets for multiple input locations, filters load time histories, selects critical areas and analyzes for fatigue life. Several case studies have been completed. The results show that the variations are consistent with the accuracies in finite element analysis, road load data acquisition, and fatigue calculation methods.

There is a trend in the automotive industry to reduce the number of physical prototypes and to rely more on Computer Aided Engineering (CAE) for sizing and final design of vehicle structures. The traditional deterministic approach does not necessarily clarify the degree of variability and conservatism. With small variability in influence parameters and a design factor for final design, the approach may be over conservative resulting in weight and cost penalty. On the other hand, with large variability and the same design factor, the deterministic approach may not satisfy durability requirements. It is important to identify the variability of all factors including road loads and sensitivities of the control parameters, and to minimize their effects on durability so that fatigue life distribution meets the durability requirements.