OPTIMUM DESIGN OF SANDWICH COMPOSITES FOR MAXIMUM BIAXIAL WRINKLING LOAD USING SIMULATED ANNEALING

Sandwich composites encounter some instability modes not found in compact laminates. One of these is facesheet wrinkling where the faces experience buckling of much shorter wavelength than those of general instability of the panel. In most aerospace and marine applications, sandwich panels are under lateral loading so one of the faces will be under tension and single-sided wrinkling can occur. In this study, this kind of wrinkling is considered. This paper uses simulated annealing (SA) optimization method to find the optimal stacking sequence of a sandwich panel for maximum wrinkling load under biaxial loading. Simulated annealing is a random search method based on the way in which a metal cools and freezes into a minimum energy crystalline structure (the annealing process). SA's major advantage over other methods is the ability to avoid becoming trapped in local minima so it is most useful in the optimization of problems with large discrete design spaces, such as stacking sequence optimization of laminated composites. To verify the algorithm, symmetric balanced laminated sandwiches are considered for the optimization problem and the results are compared to some arbitrary designs. Also the effect of some SA parameters on the optimization trend is studied.

Keywords:

sandwich , composite , simulated annealing , optimization , wrinkling