Research And Application Of Structural Topology Optimization Based On BESO Method

In the structural lightweight design and type selection stage, topology optimization can flexibly provide a reasonable and enlightening structure form. Considering topology optimization results served as a reference to conceptual design, the choice of topology configurations greatly influences the main performance of product design. Therefore,topology optimization at a higher design level is of more value than the subsequent shape and size optimizations, and is more attractive to the engineering field. Topology optimization of continuum Structures is one of the hotspots and difficulties in the field. Based on the bi-directional evolutionary structural optimization, this paper expands the theory into multi-objective and nonlinear topology optimization and studies the practical engineering application of the method.Firstly, the basic principle of the bi-directional evolutionary structural optimization is studied by anatomizing its structural evolution strategy and concluding the basic flow of algorithm. Meanwhile, the numerical problems of evolutionary method are analyzed and the solution schemes are proposed; the key steps of unit coding in the finite element analysis process are explained. Thereby, bi-directional evolutionary structural optimization based on the stiffness and the modal analysis is studied. Secondly, the relevant theory of multi-objective optimization is applied into bi-directional evolutionary structural optimization design. The implementation scheme and optimization process of multi-objective evolutionary structure topology optimization are put forward. Thereby, two common situations, namely the static load with multiple conditions and the both static and dynamic conditions, are studied based on the multi-objective evolutionary structure topology optimization method. Thirdly,by adopting the unit "hard kill" bi-directional evolutionary method, the stiffness topology optimization of nonlinear structure is studied. The nonlinear structural topology optimization models under force control and under displacement control are established, of which sensitivity number formulas are deduced. The evolutionary optimization process of nonlinear structure is put forward. Through numerical examples, structural topology optimization is studied in four finite element analysis situations: linear, geometrically nonlinear only,materially nonlinear only and coupled geometrically and materially nonlinear. Finally, the practical engineering application of the evolutionary topology optimization is studied by the interaction of Python and ABAQUS, in which Python as the scripting language of ABAQUS software is used to compile the algorithm of bi-directional evolutionary structural optimization and ABAQUS to perform the finite element analysis. The interaction process of Python and ABAQUS is connected employing the commands through the script interface.The method can realize the complex two-dimensional and three-dimensional structural topology optimization.By extending the bi-directional evolutionary structural optimization into multi-objective and nonlinear structural topology optimization, the study shows that bi-directional evolutionary structural optimization has a good adaptability in continuum structure optimization, and the implementation of the software provides reference for engineering practice. All in all, the study not only enriches the evolutionary structural optimization theory but also broadens its range of application.