RELIABILITY-DESIGN OF FIBER-REINFORCED COMPOSITES

The anisotropy of fiber reinforced composites is often designed for so me special loading conditions to obtain high strength or other propert ies. On the other hand, the anisotropy also brings about high sensitiv ities to loading conditions. This leads to the necessity to take accou nt of the uncertainties of loads and some other design parameters. The reliability design is effective for this type of problems. This paper deals with the optimum configuration design of fiber reinforced lamin ates under probabilistic conditions of loads and material properties. A multiaxially laminated composite is treated as a series system. The Tsai-Wu failure criterion is adopted as the limit state function of un idirectionally oriented plies in the laminate. A multiple-checkpoint m ethod is used to estimate the system failure probability. An optimizat ion problem is defined to determine the number of fiber orientation ax es, orientation angles, and ply ratios in a laminate. The solution pro cedure is proposed and its validity is demonstrated through numerical examples.