Evolution of constrained layer damping using a cellular automaton algorithm

Abstract

Constrained layer damping (CLD) is a highly effective passive vibration control strategy if optimized adequately. Factors controlling CLD performance are well documented for the flexural modes of beams but not for more complicated mode shapes or structures. The current paper introduces an approach that is suitable for locating CLD on any type of structure. It follows the cellular automaton (CA) principle and relies on the use of finite element models to describe the vibration properties of the structure. The ability of the algorithm to reach the best solution is demonstrated by applying it to the bending and torsion modes of a plate. Configurations that give the most weight-efficient coverage for each type of mode are first obtained by adapting the existing 'optimum length' principle used for treated beams. Next, a CA algorithm is developed, which grows CLD patches one at a time on the surface of the plate according to a simple set of rules. The effectiveness of the algorithm is then assessed by comparing the generated configurations with the known optimum ones.

Evolution of Constrained Layer Damping Using a Modified Cellular Automata Algorithm

“…Intuitive point of view, the optimization result of the modified CA algorithm has a better consistency with the high stress area of the host plate. The optimization result using modified CA algorithm is also more in line with theoretical analysis in literature [7]. With the predetermined treatment coverage of 10%, the 7 th , 8 th and 9 th modal frequencies and structural modal loss factors were obtain by the CA-2 and the modified CA algorithm shown in Table 2.…”

“…The basic idea of CA algorithm for CLD optimization is to add a CLD patch (cell) on the host structure, then other patches will grow along with the highest damping effectiveness, which turn out to be a reasonable CLD treatment ultimately. Chia [7,8] had an in-depth study on optimization of shell structures utilizing CA algorithm, and put forward CA-1, CA-2, CA-3 and CA-4 four kinds of regional patches growing modes. The basic process can be summarized as follows 1) Algorithm start: adding a single CLD patch to the plate finite element (FE) mesh at the point of highest modal strain energy density (SED); 2) Regional growth: take the current grown patches as core, add one or more patches in the Moore neighborhood each time until the entire Moore neighborhood are traversed, then the patch or patches with the highest damping effectiveness are selected for the next iteration; 3) Continuous growth: continue regional growth until the damping effectiveness ceases to give an increment when adding a new patch; 4) Search a new start: search a new start at the point with the highest SED in stay-out region; 5) Repeat steps 2-4 until meeting the predetermined stop condition.…”

“…Zheng [6] used GA to optimize the location of ribbon CLD, number and aspect ratio of cylindrical shell structure. Chia [7,8] optimized CLD treatment on shell structures and got a good result based on CA algorithm. Li [9] developed the former studies, improved the adaptability of CA algorithm for CLD optimization.…”

A novel viscoelastic damping treatment for honeycomb sandwich structures

“…They proposed an optimised solution for the position of CLD on simply supported plates thanks to a topographical optimisation method. The cellular automaton method is particularly well suited to this problem, and has been implemented by Chia et al [16], [17] to identify optimal weight-efficient CLD configurations for plates with free boundary conditions using the loss factor as objective function. 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.…”

Modal strain energy based methods for the analysis of complex patterned free layer damped plates

“…Partial or complex patterned damping patches at selected locations are therefore more desirable than a full covering layer. Topology and cellular automaton optimization applied to damping treatment surfaces (Chia et al 2008;Lumsdaine 2002;Wardle and Tomlinson, 1997) lead to irregular and complex-patterned final shapes of the CLD and/or FLD coatings.…”