Research on the Damage Detection Method on Existing Girder Hoisting Machine

Research purposes:The structural damage of large-tonnage girder hoisting machine,such as surface corrosion,welding crack,steel crack,are difficult to detect and recognize,resulting in unnecessary engineering accident.With reference to the structural features,the ANSYS was used to set up the finite element model for the girder hoisting machine,the different level structural damage on the different structural position was analyzed.The impact of the structural damage on the dynamic characteristics and main girder deflection were researched,then the damage detection method was put forward based on the research results.Research conclusions:(1) The change of dynamic characteristics can be used to identify the structural damage,but it can not determine the location of damage.(2) The vibration mode of the girder hoisting machine changes with the structural form,then the frequency change caused by structural damage is obvious on different vibration mode with the different structural form.(3) Based on the research results,the deflection curve of the main girder can be used to identify the structural damage and to determine the location of one-point damage and multi-point damage.(4) This research result is helpful for structure inspection test and condition assessment of existing girder hoisting machine.