Topology Optimization Of Viscoelastic Constrained Layer Damping Structure

Viscoelastic constrained layer damping(CLD)treatment can effectively improve system damping,which is an important means of supressing structure vibration and noise in modern industrial area.The research of constrained layer damping structure has always been focused on the CLD material,which is covered on the surface of the whole structure,However,when the CLD material is attached to the partial position,it will not only reduce the total mass of the structure,but also get a better damping effect,Therefore,it is of great significance to use topology optimization method to seek the optimal layout of CLD material.In this dissertation,the topology optimization design method of viscoelastic constrained layer damping structure is investigated,it mainly included:(1)Using complex modulus model to represent the constitutive law of viscoelastic material,the finite element model of the structure with viscoelastic constrained layer damping treatment is established by energy method.Furthermore,complex eigenvalue method is adopted to analyze the contributions of natural frequency,loss factor and response on the resonant frequencies and response level,and the correctness of the model is verified by calculation and experiment.Subsequently,the impact of the consumption and distribution of CLD material on the natural characteristics of damping structure is calculated,and the necessity of optimizing the layout of viscoelastic constrained layer damping material is illustrated.(2)The maximum of modal loss factor is considered as the objective function in the topology optimization model of the structure with viscoelastic material treatment,which is established based on Evolutionary Structural Optimization(ESO),modal strain energy method is adopted to calculate the ensitivity of the objective function,using mesh-independent filter method to remove checkerboard pattern and the mesh-dependent problem,the ESO is proposed to search the optimal layout of CLD material of the plate with viscoelastic constrained layer damping treatment,which is taken as the research object,and the results are verified through experiments.(3)The minimizing the reciprocal of modal loss factor is considered as objective function in the topology optimization model of the structure with CLD treatment is established by SIMP interpolation model.The parameters such as moving limit constants and volume constraints are modified in this dissertation.Subsequently,the optimal layout of CLD material of the cantilever plate is investigated by Variable Density Method(VD),and the correctness of the model is verified by experiment.Furthermore,the results obtained through the VD method and ESO method are compared.The comparison result shows that the proposed VD method can achieve a better layout of CLD material than that of ESO method,as well as optimization efficiency.(4)For the viscoelastic damping structure of the panel of the aircraft inlet,the topology optimization model is established with minimizing the reciprocal of modal loss factor as objective function.The damping performance of the optimized results and the existing structures are compared and analyzed,the results shows that it is practical to seek the optimal layout of CLD material by topology optimization method to suppress vibration of the inlet wall,decrease the vibration stress,and improve the anti-vibration fatigue capability.