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.
The principal stress magnitudes and directions at any point on a vehicle are highly dependent upon simultaneous magnitudes and directions of the road loads. The principal stresses and the corresponding principal planes for an element are tracked for the entire load-time spectrum and a critical plane is selected for the finite element. All simultaneous load channels are maintained in the procedure. The life contours are plotted for visual display and are very useful to the analyst, and the design engineer.