Optimization of thickness and delamination growth in composite laminates under multi-axial fatigue loading using NSGA-II

Employing NSGA-II, this paper aims to achieve a damage tolerant structure enjoying maximum delamination resistance and thinness; therefore, we simultaneously define minimization of laminate thickness and delamination growth as objective functions. Fiber orientation angle, ply thickness, and stacking sequence are chosen as design variables. The authors consider symmetric glass/epoxy laminates with middle layers containing a single matrix crack. By applying multi-axial fatigue loading, the initiation and growth of local delamination from the tip of the matrix crack in the damaged ply interface became possible. Finally, it is indicated that NSGA-II has good convergence with damage optimization in cracked glass/epoxy composite laminates.