Enhancing_Computational_Efficiency_In_Modal_Transient_Analysis_Through_Nastran_Restart_Method

Vehicle operation occurs in a highly dynamic environment, necessitating the use of dynamic simulation methods for accurate durability analysis. In the automotive sector, predicting structural life and damage during the design phase is essential to meet warranty requirements and ensure long-term reliability. To replicate real-world loading conditions, the industry employs torture track recipes—specialized test tracks designed to simulate extreme road conditions. Data collected from these tests, in the form of time-domain road excitations, is used for digital validation of vehicle structures. Given the limitations of current computational resources, simulating vehicle durability tests and performing structural fatigue life assessments require efficient methodologies and advanced CAE tools. Modal transient analysis in MSC Nastran offers a practical solution for evaluating time-dependent dynamic responses of vehicle structures, particularly the Body-in-White (BIW). This paper presents an effective and resource-conscious approach to vehicle dynamic durability analysis using the restart method in modal transient analysis. Although this technique has been validated across multiple programs, this paper presents two case studies to demonstrate its feasibility and accuracy in stress analysis and fatigue damage prediction. Also the automation script is designed to initiate the cold start run, followed by the automatic execution of multiple restart runs. The results confirm that the restart method significantly reduces runtime while maintaining analytical fidelity, making it a viable option for modern automotive durability simulations.