Research On Structural Topology Optimization Design Of Crawler Frame For Engineering Machinery

Crawler travelling device has the characteristics of sufficent load capacity, good structure stiffness, low ground pressure, excellent adhesive performance to the ground, good passing ability, which leads to the fact that crawler travelling device has been widely used in engineering machinery. Crawler frame is one of significant components of crawler travelling device. It is vital to optimize the strcture of crawler frame to increase its load capacity. The method of topology optimization is adopted in this paper to properly distribute the material in crawler frame, aiming at improving the load transmission path and then enhancing the load capacity.Crawler frame has complicated structural form, different working conditions varying largely in loads. The topology optimization problem of crawler frame belongs to a typical multi-objective optimization problem. It may be difficult to aqiure a satisifying structural form through routine topology optimiaztion method. A new optimum design method is proposed to deal with such problem, namely modifid comprmise programming approach based on satisfaction theory, to implement the topological optimization of crawler frame under multiple loading cases. The main works of the dissertation are as follows:(1) Based on interpolation schemes of variable density method, the mathematic model of minimize complaince topology optimization has been set up. The method of moving asymptotes has been chosen as the numerical algorithms to solve the model. Numerical problems and its solutions have been studied in solving topology optimization problem through variable density method.(2) Based on the theory of multi-objective optimization, the mathematic model of minimize compliance problem under multipule loading cases is set up using compromise programming approach. The basic satisfaction theory and mathematic expression of satisfactory degree have been studied.(3) After analyzing the topical working conditions of a particular crawler frame, the FEA model of the topology optimization is established in OptiStruct software, followed by the solution of the minimize complaince optimal problem under single loading case. By comparing the optimal results, proper optimal parameters have been chosen. (4) Based on satisfaction theory, the compromise programming approach is modified to abtain dynamic weight of each sub-objective, which can eliminating subjective factors. The multi-objective optimal model is solved by OptiStruct, acquring the optimal material distribution form under multipule loading cases.(5) Based on the result of topology optimization, the three-demensional model is reconstructed. Size opitmizaton of plates in key position is carried out, followed by the static analysis of the modified structure. The comparison of the results between optimized after and before shows the effect of topology optimization and size optimization.