Static and frequency optimization of folded laminated composite plates using an adjusted Differential Evolution algorithm and a smoothed triangular plate element

The paper proposed a coupled numerical method for the static and fundamental frequency optimization of folded laminated composite plates. In the optimization schemes, the objective function is to minimize the strain energy for static problems and to maximize the fundamental frequency for free vibration problems. The fiber orientations are taken as design variables which are discrete integer values between −90° and 90°. For analyzing effectively the behavior of folded laminated composite plates, a recently proposed smoothed triangular plate element, named the cell-based smoothed discrete shear gap method (CS-DSG3), is applied. For searching the optimal solution which contains discrete integer values, an adjusted Differential Evolution (aDE) algorithm is proposed by integrating the conventional Differential Evolution (DE) for searching the optimal continuous solution with a novel technique for handling discrete integer variables and a mutation strategy. The reliability and effectiveness of the proposed aDE are verified by comparing its numerical results with those of other algorithms in literature such as Genetic Algorithm (GA), Particle Swam Optimization (PSO), etc.