Structural Performance Analysis And Optimization Design Of Main Girder With Corrugated WEB For Gantry Crane

Box girder gantry crane is widely used in many fields,such as construction,production,logistics and so on,because it has the advantages of high safety and high stiffness.The weight of the metal structure of box girder gantry crane usually accounts for more than 60%of the weight of the whole machine,and some large gantry cranes are up to 90%,therefore,it is necessary to study the lightweight.There are many methods for lightweight design of crane metal structure,including the use of high strength alloy materials,the improvement of processing technology and the adoption of more favorable structural forms,etc.While the first two methods are often subject to cost and existing processing technology conditions,therefore,it has become the focus of research to improve the lightweight structure of gantry crane.This paper draws on the widely used box girder structure with corrugated web in bridge and housing construction,and studies the lightweight of box girder gantry crane.In this paper,a cantilever box type double girder gantry crane with a rated weight of 40t and a span of 30m is designed.A suitable corrugated shape and size are used to design the corrugated web gantry crane.Establishing the finite element model of traditional gantry crane and corrugated web gantry crane by ANSYS,on which basis,the static strength,static stiffness and weight of two kinds of gantry cranes are analyzed and compared.The results show that the static strength and static stiffness of the two kinds of gantry crane meet the requirements,however,the static strength and static stiffness of corrugated web gantry crane decreased slightly.Compared with the traditional gantry crane,the corrugated web gantry crane frame saves steel 7776kg and reduces the weight by 8.01%.The optimization design of corrugated web gantry crane and traditional gantry crane is carried out by using finite element analysis software ANSYS and multidisciplinary optimization platform ISIGHT.After optimization,compared with the traditional gantry crane,the corrugated web gantry crane frame saves steel 6381kg and reduces the weight by 7.56%,and the lightweight design is realized.The static and dynamic performance of the optimized corrugated web gantry crane is studied.First of all,ANSYS is used to check the static strength and static stiffness of corrugated web gantry crane,and the nonlinear buckling analysis of corrugated web is carried out by using the method of uniform defect mode in which the influence of material nonlinearity and geometric nonlinearity are considered.The results show that the static strength and static stiffness of the optimized corrugated web gantry crane are satisfied,and the local stability of the corrugated web is satisfied too.Then,the modal analysis of the corrugated web gantry crane is carried out by block lanczos method,and the first 8 natural frequencies and vibration modes are obtained.The seventh order vibration mode is the vertical vibration of the gantry crane and the natural frequency is 3.727Hz,so the dynamic stiffness of gantry crane can meet the requirement of 2Hz-4Hz.Finally,ANSYS is used to analyze the dynamic response of the gantry crane when the cargo is suddenly out of the ground.Considering the uncertainty of material properties,load and size parameters of corrugated web gantry crane,the reliability analysis of the corrugated web gantry crane is carried out by using the PDS module of ANSYS,which is based on the strength failure theory.The results show that uncertainty of the lifting weight Q is a key factor affecting the reliability of gantry crane structure,and reliability of corrugated web gantry crane is 99.207%when the maximum weight of lift is 10%,while reliability of corrugated web gantry crane is 99.944%when overloading is strictly forbidden.