ABSTRACT
A fiber-reinforced laminated composite material system is made up by stacking thin plies with different ply orientation angles. Its structural property depends on the laminate configuration such as ply thickness; ply orientation angles and the stacking sequence. Their property is known to have larger variations than that of conventional materials and very sensitive to the loading direction. Therefore, it is important to consider the variations on designing the laminated material system. This paper demonstrates the importance of considering uncertainties on designing the laminate configurations through reviewing the researches by the authors and their coworkers. Effects of variations of material properties, applied loads and ply orientation angles on the structural reliability subject to the in-plane first ply failure criterion, the buckling loads and the bending failure due to an initial imperfection are demonstrated. Moreover, the importance of considering reliability is illustrated by comparing the reliability-based optimum with the deterministic optimum designs.
