The Research Of Residual Life For Boom Structure Of Large Crawler Cranes

As one of the most staple equipment in construction, crawler crane are of more significant in China. With the development of fundamental facilities, the security of a crawler crane is concerned widely. Booms are the most decisive parts of crawler cranes to carrying structure. The method of residual life evaluation for cranes, especially for large cranes, has been a challenge for engineers. As the fast development of modernization, crawler cranes are more likely to work fully loaded and to work more frequently. Most of them work mostly at a high or over loaded tress condition. So it is necessary and urgent for us to evaluate the fatigue life of boom structures of crawler cranes. And also, based on the former research, some important theories are brought forward.This thesis takes the theory into practice to resolve problems in productions, through the boom of LS-518J 136t crawler crane owned by Offshore Oil Engineering Co. Ltd.(1) The modern methods of residual life evaluation are gathered in the paper, and the advantages and disadvantages of these methods are concluded.(2) According to the quality of a crawler crane, the Account-Normal Stress Approach, which fits the high cycle fatigue condition excellently, is used in the research. A finite element method is integrated to solve the problem of boom fatigue life. The method is used in calculating the fatigue life of the boom on LS-518J 136t crawler crane.(3) The Analysis flow of virtual fatigue endurance integration is used to calculate the fatigue life and fatigue damage in the simple working condition. And feasibility of this project is validated by comparing the counting result and loading record in probability theory.(4) The life of damage and stress value in different angle is obtained through makeing the fatigue analysis to T, K and the tie-in weld model in dangerous position respectively by the welding line analysis module in MSC.Fatigue software. The method is feasible through the simulative experimentation in the last and also the cause of cracks is discussed.It is found and established of the system about residual life evaluation for large cranes' booms in the thesis. The method is adapted for all the crawler cranes currently being used. And it can be a guidance theory in evaluating the life of a crawler crane. Also, the content in this paper can be referenced by other life evaluation for booms and even the whole machine.