Topology optimization of PCLD on plates for minimizing sound radiation at low frequency resonance

2018

Shock and Vibration

An acoustic radiation model of a cavity with a flexible plate treated with constrained layer damping (CLD) is developed by a combination of finite element method (FEM) and boundary element method (BEM). An acoustic topology optimization model is established with the objective of minimizing sound radiation power at specific modal frequency and design variables defined as locations of CLD treatments. The evolutionary structural optimization (ESO) method and genetic algorithm (GA) are employed to search optimal CLD configurations. Sound power sensitivity for CLD/plate is derived to determine search direction in ESO optimization procedure. The optimal CLD layouts for the flexible plate with two different boundary conditions are obtained and analyzed. Computational time, optimal layouts, and minimum sound power obtained using ESO and GA are compared. The results demonstrate effectiveness of the two methods, and ESO is more efficient to obtain deterministic and more practical optimal CLD material layouts for minimizing sound radiation power. The influences of CLD materials thickness and exciting force locations on optimal results obtained using ESO are discussed in detail. It is shown that the optimal rejection ratio varies with thicknesses of CLD materials and distribution of normal velocity of the flexible plate. Variation trend of the optimal rejection ratio is opposite for the two boundary conditions.

Section: Discussion Of Optimalmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Comparative Study on Acoustic Optimization and Analysis of CLD/Plate in a Cavity Using ESO and GA

Zhang

Wang

2018

Shock and Vibration

“…where [M] is the global mass matrix, [K R ] is the real part of the global stiffness matrix, [K I ] is the imaginary part of the global stiffness matrix, and X is the nodal displacement vector. en, the rth modal loss factor, which represents the vibration energy dissipation ratio of the modal, can be derived using the FE-MSE method as follows [11]:…”

Section: Problem Statementmentioning

confidence: 99%

“…Ling et al [9] extended Mohanmmed's work to optimize the viscoelastic materials distribution in CLD using the solid isotropic material with penalization (SIMP) model and the method of moving asymptote (MMA) approach. Lots of optimization approaches for vibration and noise control using damping treatments [10,11] are carried out based on the SIMP method due to its easy implementation.…”

Section: Introductionmentioning

confidence: 99%

Topology Optimization of Free Damping Treatments on Plates Using Level Set Method

Pang

Yang

et al. 2020

Shock and Vibration

Self Cite

Application of level set method to optimize the topology of free damping treatments on plates is investigated. The objective function is defined as a combination of several desired modal loss factors solved by the finite element-modal strain energy method. The finite element model for the composite plate is described as combining the level set function. A clamped rectangle composite plate is numerically and experimentally analyzed. The optimized results for a single modal show that the proposed method has the possibility of nucleation of new holes inside the material domain, and the final design is insensitive to initial designs. The damping treatments are guided towards the areas with high modal strain energy. For the multimodal case, the optimized result matches the normalized modal strain energy of the base plate, which would provide a simple implementation way for industrial application. Experimental results show good agreements with the proposed method. The experimental results are in good agreement with the optimization results. It is very promising to see that the optimized result for each modal has almost the same damping effect as that of the full coverage case, and the result for multimodal gets moderate damping at each modal.

“…Usually, optimal configurations of positions and thicknesses for CLD materials cannot be found together using topology optimization methodology. [13][14][15][16][18][19][20] Therefore, for sound optimization problem of CLD structure, a hierarchical optimization strategy is proposed. First, a topology optimization algorithm is employed to find optimal positions of CLD treatments on the base plate, subject to added mass constraints; furthermore, the areas on which CLD materials are pasted are divided into several subareas; an evolutionary algorithm can be used to search optimal thicknesses of CLD materials, subject to the same mass constraint.…”

Section: Optimization Strategymentioning

confidence: 99%

A hierarchical optimization strategy for position and thickness optimization of constrained layer damping/plate to minimize sound radiation power

Zhang

Tang

Advances in Mechanical Engineering

2018

A hierarchical optimization strategy is proposed to optimally design constrained layer damping materials patched on the base plate for minimizing sound radiation power. A sound radiation optimization model is established by taking positions and thicknesses of constrained layer damping materials as design variables, and added mass as constraints. The hierarchical optimization procedure is implemented, in which evolutionary structural optimization method is employed to get optimal position layouts of constrained layer damping materials, and genetic algorithm is used to find optimal thickness configurations of constrained layer damping materials by taking the plate with optimal position layouts of constrained layer damping materials as initial structure. Two sound power sensitivities are formulated and compared for position optimization. Numerical examples in which unweighted/weighted objective functions are considered are presented, optimal positions and thickness configurations of constrained layer damping materials patched on the plate are obtained and discussed. The results demonstrate that the proposed strategy is very effective to achieve larger sound power reduction by reconfiguring the thickness of constrained layer damping materials for the results of position optimization.