Fatigue Durability Analysis of a Frame Based on Multi Body Dynamics

摘要

A fatigue analysis procedure for a frame based on virtual prototype and multi-body dynamics is established. The first 5 modes frequencies of the finite element model are calculated and verified by experimental test. The frame model is turned into a flexible body. A rigid flexible coupling model is established with suspensions, tires and the flexible frame body. The dynamic response of the model is analyzed in class D road at a uniform motion, the load-time histories of the connected locations are extracted; The S-N curve of material is fitted through the tensile strength limit; combined with the stress distribution of unique load, the dangerous positions and theirs fatigue life are predicted. The result shows that the frame damage hotspots are mainly distributed in the bracket connected with the body, frequency domain energy of connected location load is within 18Hz, the minimum fatigue life mileage is km. The result has a guiding significance for the research of the fatigue durability of vehicle frame.