Simultaneous Durability Assessment and Relative Random Analysis Under Base Shake Loading Conditions 2017-01-0339
For many automotive systems it is required to calculate both the durability performance of the part and to rule out the possibility of collision of individual components during severe base shake vibration conditions.
Advanced frequency domain methods now exist to enable the durability assessment to be undertaken fully in the frequency domain and utilizing the most advanced and efficient analysis tools (refs 1, 2, 3, 4, 5). In recent years new capabilities have been developed which allow hyper-sized models with multiple correlated loadcases to be processed. The most advanced stress processing (eg, complex von-Mises) and fatigue algorithms (eg, Strain-Life) are now included. Furthermore, the previously required assumptions that the loading be stationary, Gaussian and random have been somewhat relaxed. For example, mixed loading like sine on random can now be applied.
The check for “collisions” has previously been done separately with the resultant “doubling up” of the analysis being both time consuming and cumbersome.
However, new technological advances now make it possible to do both these calculations at the same time and this paper will present results for an exhaust model analyzed using NASTRAN. The fatigue and random response assessment will be done using a new feature in the CAEfatigue VIBRATION (CFV) analysis toolkit (ref 6).