FREE-VIBRATION ANALYSIS AND SHAPE OPTIMIZATION OF VARIABLE THICKNESS PLATES, PRISMATIC FOLDED PLATES AND CURVED SHELLS .2. SHAPE OPTIMIZATION

A robust computational tool which integrates FS analysis, parametric c ubic spline geometry definition, sensitivity analysis and mathematical programming is developed for the optimization of the shape and thickn ess variation of prismatic folded plates and curved shell structures. The objective of the optimization process is to maximize the fundament al frequency. Both thickness and shape variables defining the cross-se ction of the structure are considered. The analysis is carried out by using curved, variable thickness finite strips, formulated and tested in Part 1 of this paper. To obtain the optimal shapes, semi-analytical sensitivity calculations are used in conjunction with a sequential qu adratic programming optimization algorithm. Optimal shapes are present ed for several shells and folded plates of variable thickness.