Optimum Layout of Partially Covered Sandwich Beam with Constrained Layer Damping

Abstract

In this paper, an optimization study of partially covered beam with a constrained viscoelastic layer is presented. An energy approach and Lagrange’s method are used to establish the governing equation of motion of a CLD covered beam, and the assumed modes method is employed in solving the equation to obtain the modal loss factors which are used as the objective of optimal layout. A genetic algorithm of big mutation is employed to search for the optimum of the patch’s location, the thicknesses of both the constraining layer (CL) and the viscoelastic layer (VL) and the shear modulus of the viscoelastic material with the restriction of added volume of the total CLD treatment. Numerical results show that the optima of the design variables are highly relevant to each other. The thinner constraining layer requires a softer viscoelastic material for an optimal damping treatment. The variation of the CL thickness decreases slowly and that of the VL thickness increases with the increase of the thickness of the CLD treatment. One end of optimal damping treatment locates closely one end of base beam.

Free vibration analysis of embedded and co-cured perforated damping sandwich composite beam

“…Zheng, et al 20 studied the effects of two damping patches with different length ratios as well as the spacing between the two patches on the damping performance. Hou, et al 21 optimized the location of damping patch and the thickness of viscoelastic layer. Park 22 found that discontinuous damping beam could be more effective and economical for vibration control than a continuous damping beam if the damping patch was located at the free edge of the cantilever beam.…”

A novel viscoelastic damping treatment for honeycomb sandwich structures

“…The dimensions and locations of CLDs were taken from the original studies and implemented pro rata on the beam and plate used herein, as illustrated in tables 2a and 2b respectively. For example, Hou et al [19] identified a CLD which stretched from 0.4 to 0.5159 of the total length of their simply supported beam, and this was reconfigured to be the same proportion of the beam used in this study. Some of the literature studies did not optimise parameters such as the thickness of the viscoelastic layer (for example Zheng), but will be explored and optimised in this study.…”

“…It then decreased rapidly as more rows of cells were filled. A compromise solution was selected arbitrarily between maximal loss efficiency and maximal added mass, specifically was 5 rows filled with inserts (out of 17) for the beams and 6 rows filled (out of 19) for the plates. These configurations were used in further comparisons.…”

“…Kim also used a topology optimisation in order to find the best configuration of CLD on a fully clamped and cantilevered plate [18] that give the highest modal loss factor for a minimal increase in mass. A Genetic Algorithm was used by Hou et al in order to minimise the vibrational energy of a simply supported beam [19] and plate [20] damped with CLD. The location of the CLDs was determined with a restriction on the mass added.…”