基于Battelle结构应力法的起重机桁架臂寿命评估-机械制造及其自动化专业论文.docxVIP

基于Battelle结构应力法的起重机桁架臂寿命评估Fatigue 基于Battelle结构应力法的起重机桁架臂寿命评估 Fatigue Life Assessment for Crane Lattice Boom Based on Battelle Structure Stress Method Abstract Lattice boom eFal℃its widely used 111 various f论lds of natioml econolille construction． Lattice boom，as an important bearing part,is often subjected to alternating load effects， fatigue is the main failure mode ofdamage．According to the design standards，craile design life belongs to the category of high-cycle fatigue，the S·N curve method fiom fatigue test data is the main method of fatigue assessment．By comparing multiple fatigue standards，such as ABS，DN V，BS7608，IIW，API，AWS ASM E，etc．，it is significant to find suitable life assessment method for lattice boom welded pipe structural．By combing with K-joint fatigue test data．it is found that Battelle slructural stress method based on ASME standard is more suitable for K-joint life assessment than the ABS，DNV，IIW surface interpolation hot spot stress method． 25t-level offshore platform crane is selected and studied in this paper．Ttle equivalent structural stress transformed by correction factors is used for the evaluation of stress． combined with the rmin S-N curve．it is completed for fatigue life assessment of 1 6 welds in four boom hazardous areas under five different conditions．The main works ofthis paper as follows． (1)By comparing multiple fatigue standard documents(such ABS，DNV，BS7608， IIW，APl，AWS，ASME etc．)，the traditional nominal stress S—N curves corresponding to the crane lattice boom pipe joint cannot be found．For pipe joint fatigue assessment,the hot spot siress method is recommended and the corresponding S—N curves are provided in the fatigue standards，such as surface extrapolation interpolation hot spot stress S-N curves in ABS，DNV and B$7608 and the main S．N curve based on Battelle structural stress method in American standard ASME． (2)Based on several different methods in standards，the structural stress along K-joint weld toe is calculated under