SHACKLES FRACTURE ANALYSIS IN LIFT

The serious accident occurred during the engine pedestal of 364.8 t was hoisted into ship,which lead to casualties and pedestal seriously break. The chemical analysis,metallograph examination and fracture analysing method was used to analyze and assess material,fracture mechanism,microstructure etc. The security was appraised from two aspects of fracture toughness and mechanics. The metallographic examination verified that forge quality of shackles was poor,the appropriate heat treatment of shackles was not carried on,and there existed weld phenomenon and defect of welding micro-crackles in the inflection point of shackles. A great deal of above-mentioned factors cause to decline bearing capacity of the shackle and its security and the static load examines didn′t reach the technology requirement of JB 10603-2000. It was also verified by fracture mechanics calculation under above-mentioned conditions that the maximum depth of crack of actual fracture shackle had already been very close to the length of critical crackle allowed. Emergence course,fracture order of parts in the fracture accident,etc. had been analysed and discussed further on above-mentioned results. Shackle G ruptures at first in the accident,secondly shackle D;later,bolt B,E,F ruptured by bigger crooked load after shackle G and D ruptured.