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

Abstract

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.

Sound Radiation Analysis of Constrained Layer Damping Structures Based on Two-Level Optimization

“…The CLD/plate is discretized into 32 × 24 finite element meshes by using a four-node quadrilateral composite element [23] with seven degree of freedoms (DOFs) per node, and the uniform-sized boundary elements are used at the upper surface of the CLD/plate. The fully treated CLD/plate is selected as the initial design, and the target additional mass fraction is set to be δ2 = 0.5 in the global optimization procedure.…”

“…Furthermore, it is difficult to optimally design thickness and position configurations of CLD materials for a complex structure in a topology optimization problem simultaneously. Hence, the author [23] proposed a two-level strategy to optimally design topology layouts and thicknesses of CLD materials simultaneously for reducing the sound power radiated from the vibrating structure. In the first level, the optimal position layouts of CLD patches are obtained by using the ESO method, which is limited by only allowing the removal of the CLD elements.…”

“…In this paper, the work is extended based on [23], to present a systematic two-level optimization methodology to optimally design position layouts and thickness configurations of CLD materials for suppressing the sound power of vibrating structures. In first-level optimization, a modified bi-directional evolutionary structural optimization (BESO) method, which is characterized by a relaxed element removal/addition criterion, is presented to search for optimal position layouts of CLD materials pasted on the base structure.…”

TheFinite Element Modeling and Experimental Study of Sandwich Plates with Frequency-Dependent Viscoelastic Material Model

“…Zhao et al [16] proposed the finite element model for the sandwich plate by using a single-layer equivalent method, which was based on the equivalent material properties. Zhang et al [17] established a sound radiation optimization model for sandwich plates. The finite element method was used to formulate the normal vibration velocities, and the boundary element method was used to derive the sound power.…”

Dynamic Behaviour Adaptation of Lightweight Structures by Compressible Constrained Layer Damping with Embedded Polymeric Foams and Nonwovens

“…Especially treatments belonging to the family of Constrained Layer Damping (CLD) in which damping layers are forced to shear deformations while the base structure vibrates in bending modes are applied for structures with complex geometries [23,24]. Partial coverage with CLD segments of optimised shape is a common measure enabling a reduction of the mass overhead caused by the damping treatment [25].…”