It is statistical that about 50 percent to 90 percent destroy of metal structure is fatigue damage. So, people must calculate the fatigue life of metal structure correctly in order to reduce the fatigue damage accident. The fatigue life of case house bridge crane in BISC is calculated as an example in this thesis.Firstly, the actual stress history of the projecting beam’s maximal stress area is acquired by integrating the three-dimensional FEM analysis calculation and the dynamic stress test at field. Secondly, its load spectrum is gained through adopting the linear cumulative damage theory, modified p-s-N curve and the structure fatigue life analysis software(2.0 version) which was developed by author. Finally, according to the analytic result, the paper puts forth the renovation project of the projecting beam, which can increase its fatigue life.With the shell-to-solid submodeling technique, the main sternum where shear stress is maximal on main beam is analyzed. The analysis result indicates that mesh density must be restrict, and mesh length of shell element shouldn’t be widther than thickness of shell.The structure fatigue life analysis software is developed by the VC++ and MATLAB. It calls the rich function library of MATLAB to the VC++ development environment through adopting Visual matcom as the program interface. As a result, the software has the friendly interface, openness, the good expansibility and transplant.The paper offers a new correct and utility method for engineering designer to calculate the fatigue life. The new method and the software are not only applied to the metal structure, but also all types of mechanical parts. Engineering designer also can improve and extend the software according to the different equipment and work condition easily.
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