Multi-objective Topology Optimization And Performance Analysis Of Primary-secondary Structures

Primary-secondary frame-bracing-core tube system has distinct primary-secondary features,its bracing is a key component that provides stiffness and ductility control.At present,the optimization for bracing is mostly single-objective optimization,the result obtained by the optimization method can only meet the requirement of elastic stage stiffness and neglect the ductility of elastoplastic stage.Considering the shortcomings of the existing optimization methods,this paper first proposes a multi-objective optimization method based on stress and strain energy;then the multi-objective topology optimization method is used to optimize the primary-secondary frame-bracing-core tube system.The optimal bracing arrangement under different conditions is obtained,and the mechanical properties of the obtained results are analyzed.Finally the elastic-plastic analysis of the structures with different bracing arrangements are carried out,and the plastic development pr ocess of the structure and the plastic energy consumption of the components are obtained.T he specific works are as follows:Analysis of multi-objective topology optimization mechanism and select objective function.The multi-objective function based on stress and strain energy is established based on the requirement of simultaneously meeting the stiffness of the structural elastic phase and the ductility of the elastic-plastic phase.Under the combination of different weight coefficients,the BESO method is applied to optimize the structure,and the optimization results and performance indexes are compared and analyzed to obtain the optimal combination of weight coefficients that satisfying the conditions.Taking the primary-secondary frame-bracing-core tube structure with X-bracing as an example,the contribution of different component groups to structural stiffness and plastic energy is analyzed,which further verifies the rationality of the optimization area selected in this paper.Topology optimization and analyze of primary-secondary structure based on multi-objective.Based on the bracing arrangement area of the primary-secondary frame-bracing-core tube,multi-objective topology optimization under different boundary constraints,different load combinations and different types of horizontal loads are analyzed.The optimized results are transformed and the mechanical properties of the elastic pha se are analyzed.The mechanical properties and deformation characteristics of the structure with X-support,single-objective optimization and multi-objective optimization are analyzed,and the optimal bracing arrangement is obtained.Seismic failure mode analyze of multi-objective topology optimization results.The modal static elastoplastic pushover analysis and the dynamic time history elastoplastic analysis are carried out on the single-objective,multi-objective and traditional X-supported bracing structures.By means of static elastoplastic analysis,the yield order of each component in the process of plastic development of different bracing structures is summarized,and the time and duration of plastic development are compared.And the deformation of t he secondary columns and the main columns along the height direction are obtained.The plastic energy of the components in various types of structures under earthquakes is analyzed,and the optimization results are evaluated.Finally get the best form of braces arrangement.