Research of Fatigue Life Simulations Applied To Large Complex Structure

摘要

In structural design for safety and durability, the primary concern is to reduce structural fatigue damages due to random dynamic loadings during the service life of locomotive vehicle system. Rolling stocks is facing new sever safety problems, such as bogie frame structure components fracture and safety-based design optimization to durability of locomotive. The objective of the current research is to find the most efficient approach to predict structure safety with Multi-Body Simulation (MBS) and Finite Element Method (FEM). The method is implemented to evaluate bogie frame fatigue damages under dynamic stochastic loadings. The time varying boundary conditions and dynamic load history acting on the large structure can be evaluated by applying the Multi-body Simulation technique in software SIMPACK. Stress/strain analysis technology with software ANSYS yields the danger stresses in the critical locations of the structure depending on the unite loads. And modal analysis is used to determine frequencies and mode shapes of structure. Based on these danger stresses distribution and dynamic load time history, fatigue life can be estimated with Palmgren-Miner theory. The standard time history method involves stress or strain cycle counting, damage prediction, and finally life estimation in Software FE-Fatigue with factor of safety technology.