I. INTRODUCTION The rapid progress in composite materials technology continues to raise their performance potential for structural applications with the development of stronger fibers and tougher resin systems. At the same time, an understanding of damage and fracture in laminated composites is developing, which is providing guidance to material developers as well as to structural designers. With this knowledge, not only is it feasible to assess the effect of a given defect or damage on the stiffness, strength, and life of the structure, but also the laminate can be designed to be inherently more damage-tolerant.