Research On Multi-Scale Parallel Topology Optimization Of Structures Considering Transient Effects

Topology optimization is a structured and powerful tool.topology optimization provides the best material distribution in the specified design domain to obtain the best structural performance by finding the distribution of materials and voids.Topology optimization has been widely used in aerospace,electronic devices and other industries.The traditional topology optimization mainly optimizes the structure on a single scale and a single physical field.However,with the progress of industrial production,industrial parts,rockets,space shuttles,etc.are subject to thermal loads,force loads,and other physical fields.The traditional topology optimization can no longer meet its design requirements.Compared with a single scale,multi-scale topology optimization has the characteristics of light weight and large specific stiffness,and it is also more and more widely used in engineering applications.At present,most of the research on topology optimization focuses on the topology optimization problem with steady-state effects.However,in some engineering applications,the thermal load is often characterized by short-term periodic characteristics with significant transient effects,so in some cases,transient effects must be considered.Based on the above,the mathematical model of multi-scale parallel topology optimization considering transient effects is constructed in this paper,and the heat conduction structure considering transient effects and the thermo mechanical coupling structure considering transient effects are studied.Firstly,based on the steady state heat conduction SIMP interpolation model,a heat conduction SIMP interpolation model considering the transient effect is constructed.By comparing the transient heat conduction topology optimization configuration with the steady state heat conduction topology optimization configuration,the necessity of considering the transient effect is verified.Then,a multi-scale parallel topology optimization model of structures considering steady-state effects is proposed,and a macro and micro mathematical model is constructed.By dividing the macro design domain into multiple sub design domains,the same micro structure is used in the same sub design domain,which reduces the size of design variables and improves the computational efficiency.Secondly,a multi-scale parallel topology optimization method for heat conduction considering the transient effect is proposed,and then the transient temperature load is transformed into an equivalent static load,and then the equivalent heat load is applied to the topology optimization model of the transient heat conduction problem,and the sensitivity analysis is performed using the adjoint variable method.A uniform heat source quadrilateral heat dissipation optimization model was established to optimize the chip heat sink,and the results proved the feasibility of the constructed mathematical model in engineering applications.Then,the thermo mechanical coupled multi-scale parallel topology optimization method considering transient effects is proposed,with structural flexibility as the optimization objective.The dynamic load is transformed into the equivalent static load,and the equivalent static load is introduced into the multi-scale optimization model to solve the objective function and sensitivity of macro and micro optimization,which reduces the time cost of topology optimization.Finally,the reliability and practicability of the proposed mathematical model are verified by topology optimization of cantilever beam and rocket insulation layer.Finally,the thermo mechanical coupling multi-objective problem is transformed into a single objective problem through a compromise programming method,and a multi-objective thermo mechanical coupling multi-scale parallel topology optimization model considering the transient effect is proposed.The proposed topology optimization mathematical model is used to optimize the rocket insulation layer,and the gray correlation method is used to compare the weights to obtain the final topology optimization configuration with the best comprehensive performance of structural flexibility and heat dissipation weakness,The correctness of the proposed method has been verified.