The Research And Application Of Evolutionary Structural Optimization Based On Element's Properties Change Method

In recent years the topology optimization for structure has become a widely studying point in structural optimization design domain. The topology optimization can optimize the topology of structure, also the shape and dimensions to a certain extent. The topology optimization for structure is widely applied to the design of airplane, automobile etc., and play an important role in these engineering.In the thesis, evolutionary structural optimization was studied based on element's properties change method(EPCM) which synchronously decrease the elastic modulus and density, so that the topology optimization of the linear elastic structure was carried out for minimization compliance under the body force and frequency optimization,etc. The eliminating method of numerical instabilities (the mesh-dependency and checkerboard patterns, etc.) also was developed for the EPCM in the thesis.The EPCM was also applied to the topology optimization of multiple load cases and multiple objectives, topology optimization under the inertia loads for structure, the damping material optimal placement and topology optimization for constrained damping layer structure.The research and application of topology optimization method in the paper is concluded as follow.(1) The element's properties change method was developed for evolutionary structural optimization based on hard kill(HK). In the EPCM, the elastic modulus and density was synchronously decreased for all element that should be removed. The EPCM can carry out the topology optimization based on minimized the maximal stress or the compliance of structure under fixed loads and inertia loads, also the topology optimization of natural frequency and dynamic response of structure. Meanwhile, the matching sufficient condition was studied of the elastic modulus and density for all element that should be removed.(2) The sensitivity redistribution method (SRM) in references cannot deal with three dimension topology optimization for structure, and cannot achieve high order SRM. The high order SRM was presented by time after time used the first order SRM based on searching of elements and its nodes of structure. The high order SRM was not dependent on the table of weight coefficient, and suit for two dimension, three dimension topology optimization, and has ability to elminating the checkerboard patterns.(3) The discrete independent mesh filter method(DIMFM) was studied based on...