Abstract
Shapes and lay-up configurations of composite laminated shallow shells are optimized simultaneously to maximize the fundamental frequency by a simple genetic algorithm method with the elitist tactics. The shell shape is defined by a cubic polynomial and various shapes of shells with inconstant curvature radii can be expressed by varying the value of coefficient for each term. The coefficients and the lay-up configuration of the laminated shell are directly employed as design variables, and constraints are imposed on the coefficients and curvature radii to keep shells shallow. The frequencies are calculated by using the Ritz method due to its flexibleness for shell shapes. Results of the present analysis technique agreed well with experimental and finite element analysis results in terms of frequencies and mode shapes, obtained optimum solutions resulted in higher fundamental frequencies than the shells with general shapes and lay-up configurations.
