Research On Monolithic Model Based Topology Optimization Of Steady Fluid-structure Interaction With Low And Moderate Reynolds Number

Fluid-structure interaction(FSI)is a multiphysics problem involving the interaction of moving fluids with elastic or rigid structures,moving or constrained structures.FSI is a strongly coupled phenomenon,where structural deformation depends on fluid flow,and fluid flow may also depends on structural deformation.Through the analysis of the research status,it can be seen that the fluid-structure interaction optimization problems face the difficulty of implicit expression of fluid-structure interaction boundary,which brings great challenges to structural design modes,such as size and shape optimization.Topology optimization can obtain structural designs that meet the requirements of high performance by determining the material distributions in a larger structural design space,which is an important theoretical method to solve the above problem.Because of its inception,topology optimization has found application in many areas of engineering and applied science.In contrast to size optimization and shape optimization,topology optimization can be used to change the structural topology within the design domain and find the optimal layout of materials.In this paper,the monolithic model of steady-state fluid-structure interaction problem is adopted to uniformly describe the fluid and structure in the design domain,in order to overcome the difficulty of implicit expression of fluid-structure interaction boundary.The optimization of fluid-structure interaction topology under the condition of low and moderate Reynolds number(0～500)and external force(0～10~4N)in two dimensions have been realized.These are verified the correctness of the monolithic model.The main research contents are as follows:(1)On the basis of fluid mechanics,linear elasticity and monolithic description method,the monolithic model of low and moderate Reynolds number fluid-structure interaction topology optimization is established,and the numerical solution is realized by material interpolation and continuous adjoint analysis of the model,where the iterative evolution of design variables adopts the method of moving asymptotes.(2)The fluid-structure interaction topology optimization method based on the monolithic model is used to optimize the topology of the cantilever support structure in the fluid channel,and the cantilever support structure under the action of external forces in the fluid channel,and the distribution of the upper and lower wall materials of the channel.The above examples verify the correctness of the theoretical model.Optimizing the structure with minimal compliance or minimal structural elasticity under the constraint of volume fraction in the topology optimization process is the design goal.