The Experimental Andapplied Research On Safety Assessment For Metal Structures With Initial Crack On Port Crane

Port cranes can easily produce crack during their service due to being used for along time or having initial defects. Crack is one of the most common failure modesfor port cranes and it is often seen that fatigue failure and fatigue fracture areoccurred on port cranes because of crack propagation. Looking for a reasonablemethod used for safety assessment of metal structures with crack is one important andnecessary research subject for the safe management, monitoring and use of portcranes.This paper effectively integrates practical investigation, theoretical research withexperimental technology. Based on finite analysis technology, numerical computationmethods and Visual Basic program, the experimental and applied research on safetyassessment for metal structures with initial crack on port crane is conducted. Themain content and innovation include:(1) Investigating the crack faults of cranes at different domestic ports, getting thecrack positions on three typical port cranes including gantry crane, quayside containercrane and port crane, and then analyzing the rule of positions where crack easilygenerates.(2) For the actuality that the fatigue propagation research for welded crack ofQ345B steel is rarely studied in domestic, some non-standard specimens with weldedcrack are made and the fatigue propagation experiment for Q345B steel is conductedon MTS810. The recorded experimental data is used to solve fatigue propagationparameters of Q345B steel, which contributes to supplementing the blank in thesimilar research field.(3) By simulating the experimental specimens with the finite software ANSYS,especially concentrating on the simulation of crack and weld, the stress intensityfactor for different crack length is calculated. Based on this, the experimental data isprocessed and the linear regression equation of crack is confirmed, which finallyhelps to solve fatigue propagation parameters of Q345B steel with welded crack.(4) Analyzing structural stress of three typical port cranes with ANSYS,comparing the high-stress positions with investigation result before, and then determining the crack sensitive areas. The fracture mechanics is used to deduce thefatigue life evaluation for metal structures with initial crack on port cranes.(5) With VB, the fatigue life evaluation system for metal structures with crack onport cranes is programmed. This system includes four modules: crack’s checkingareas guidance, critical crack length calculation, remaining life calculation for metalstructures with crack, maintenance instruction for metal structures with crack. It is agood tool which can be well used to manage and monitor the safety of crackstructures.The research findings of this paper make contributions to research on fatiguepropagation law and safety assessment of metal structures with initial crack, whichhas some degree of reference significance and practical application value.