Crack Failure Research Of Crane Based On Finite Element Method And Fracture Mechanics

Crane is a kind of important equipment of modern industry,with the highly development ofeconomy of our country,it has been playing a more and more important role.At the same time,on account of high frequency and high load workment,there usually appears all kinds ofmalfunction,among these malfunction the most common and also the most serious is the fatiguecrack of crane metal structures,which is prone to arouse fracture which would lead to seriousincidents,so the research of fatigue crack in crane metal structures has become an importantissue of modern industry.This paper takes the depth-span number four125t×22m overheadcrane which for casting in the third rolling mill of some Corp as the object of study,and takeFinite Element Analysis software ANSYS as a tool,has analysed the reasons of the fatiguecrack,and puts forward the measures of crack arrest and repairing,and verify the feasibility ofthe measures of crack arrest and repairing at last,it comes out a reference to the research andrepairing of the same kind of fatigue crack in crane.This paper has done following works:(1) According to the results of static strength analysis by ANSYS,it finds out that highstress on the welding corner point of the main web plate and clapboard which is aroused byextrusion force between the wheel of crane and the track is the main reason of the fatigue crack.(2) Calculates the life-span of the fatigue crack on crane by linear elastic fracturemechanics,gets the designed life of the crack propagation which contain initial crack,make theactual worked life-span correspond to the theoretical worked life-span,and it comes out the factthat the crane must be repaired as soon as possible.(3) Put forward the measures of crack arrest and repairing according to theory of crackarrest and repairing, analyse the fatigue crack on crane by submodel technique of ANSYS,according to the results of stress comparison,it finds out that the stress level of the fatigue crackhas reduced to safety range,so the feasibility of repairing verified.(4) Simulate the fatigue crack by submodel and3D fracture model of ANSYS, calculatesthe stress level and stress intensity factor on crack tip, compare with threshold value of crackpropagation, further verifies the feasibility of the measures of crack arrest and repairing.