Topology Optimization Research On Main Boom Structure Of Rail Crane

The rail crane is the most capable crane at present,which is widely used in the lifting tasks of nuclear power and petrochemical industry.The main boom of the rail crane is the main bearing part,so the performance requirements are higher.The structure form of the main boom has a great influence on the performance,so the optimal design of the main boom structure is an important research direction.At present,there are few topology studies on the main boom of rail cranes,mainly focusing on the size and form optimization.In order to obtain the main boom structure with higher comprehensive performance,this paper mainly studies how to apply topology optimization in the design of large truss structure,and improve the efficiency of the process.On the basis of analyzing the characteristics and efficiency of topology optimization algorithm,the following work is carried out in this paper:(1)In the study of the continuum optimization of the main boom structure,the SIMP method was used to construct the optimization model,and the iteration of the design variables was calculated using the criterion derived from the K-T condition.Through the study of parameter control variables,it is found that the volume fraction of the optimization model is related to the moving step size in the iterative process,and a modified moving limit method is proposed to control the size of the moving limit.The calculation results show that the modified moving limit method can effectively increase the calculation speed of SIMP algorithm by more than 30%.(2)The redundancy of degree of freedom in the optimization process of the basic structure is solved,and the force analysis of the structure is carried out.The iterative criterion of ε-stress relaxation method is derived,the boundary conditions are set according to the real conditions,the topology optimization of the base structure is realized,and the problem of unstable convergence in the iterative process is solved.(3)The continuum topology optimization calculation performance is excellent,the adjustable ability is strong,but can not get trusse-like structure;The trusse-like structure can be obtained by structural optimization of truss foundation,but it is difficult to solve large-scale problems.In this paper,a new flow of topology optimization is proposed by combining the advantages of the two methods.In the design process of the truss main arm,the continuum method is used to obtain the optimal structure contour and reduce the design area in the next step.The initial base structure is generated based on the topological optimal contour.Finally,the trusse-like structure of the main boom is obtained by using the basic structure method.