Evolutionary Structural Optimization Method For Thermal-Elastic Topology Optimization Design

In the field of aerospace,new lightweight design schemes for thermal protection structures in harsh service environments have always been research hotspots in the field of structural design.With the development of computer technology and numerical simulation technology,the increasingly mature topology optimization technology has developed the innovative potential of structural lightweight design and lowered the threshold of structural innovation design.Among the many increasingly developed topology optimization methods,the bidirectional evolutionary structural optimization method(BESO)has been widely used in theoretical research and engineering practice due to its high optimization efficiency and strong universality.Based on the BESO method,this paper carried out the research on the topology optimization design of thermoelastic structure under uniform temperature field and heat conduction.The main work in the dissertation is as follows.Firstly,the research on the topology optimization design of the flexibility of the thermoelastic structure under a uniform temperature field is carried out.Chapter two derives the mean compliance expression of thermoelastic structures under thermo-mechanical coupling conditions.Based on the BESO method,an optimization model with compliance minimization is established.The adjoint method is used to derive the corresponding sensitivity expressions The variable updating and convergence criteria are discussed,and the corresponding optimization process was established.Numerical examples are used to explore the sensitivity of flexibility to temperature loads and the influence of different temperature loads and mechanical loads on the topology optimization results,which verifies the stability of the algorithm.Secondly,the structural topology optimization design considering thermal stress under uniform temperature field is studied.Chapter three presents an equivalent stress model considering thermal and mechanical loads,uses p-norm function to condense local stress.An optimization model with the maximum stress as the constraint to minimize the compliance is established.The adjoint method is used to derive the corresponding sensitivity expressions.The variable updating and convergence criteria are discussed,and the corresponding optimization process was established.The feasibility and effectiveness of the method are verified by typical numerical examples.Finally,a research on structural topology optimization design considering heat conduction is carried out.The heat conduction differential equation and finite element equation are derived.Based on the optimization design method of thermoelastic structure in the previous work,the topology optimization mathematical model and optimization process are established by taking stress constraints compliance minimization design as an example.Numerical examples under different temperature gradient loads were used to verify the feasibility of the proposed method,to demonstrate the realization of the research on the topology optimization design of thermoelastic structures considering heat conduction.