Aj. Keane, PASSIVE VIBRATION CONTROL VIA UNUSUAL GEOMETRIES - THE APPLICATION OFGENETIC ALGORITHM OPTIMIZATION TO STRUCTURAL DESIGN, Journal of sound and vibration, 185(3), 1995, pp. 441-453
In the majority of aerospace structures, vibration transmission proble
ms are dealt with by the application of heavy, viscoelastic damping ma
terials. More recently, interest has focussed on using active vibratio
n control methods to reduce noise transmission. This paper examines a
third, and potentially much cheaper method: that of redesigning the lo
ad bearing structure so that it has intrinsic, passive noise filtratio
n characteristics. It shows that very significant, broadband noise iso
lation characteristics (of around 60 dB over a 100 Hz band) can be ach
ieved without compromising other aspects of the design. Here, the gene
tic algorithm (GA), which is one of a number of recently developed evo
lutionary computing methods, is employed to produce the desired design
s. The problem is set up as one in multi-dimensional optimization wher
e the geometric parameters of the design are the free variables and th
e band averaged noise transmission the objective function. The problem
is then constrained by the need to maintain structural integrity. Set
out in this way, even a simple structural problem has many tens of va
riables; a real structure would have many hundreds. Consequently, the
optimization domain is very time consuming for traditional methods to
deal with. This is where modern evolutionary techniques become so usef
ul: their convergence rates are typically less rapidly worsened by inc
reases in the number of variables than those of more traditional metho
ds. Even so, they must be used with some care to gain the best results
. (C) 1995 Academic Press Limited