A Survey of Macroscopic Failure Criteria for Composite Materials

Abstract

Popular failure criteria of fiber-reinforced composite materials are described and compared. These criteria are empirical and should only be judged from the standpoint of the fitness to data and the ease of application. The criteria for orthotropic plies of unidirectional composites are extensions of those for isotropic materials. The quadratic criteria are considered to be the most suitable for both isotropic and composite materials. Macroscopic criteria are essential for design and for providing guidelines for materials improvements. Strictly speaking, failure criteria for multidirectional laminants are valid up to the first-ply failure envelope; i.e., before transverse cracking and delamination occur. Finally, conditions for fully optimized ply properties are easily derived from the quadratic failure criterion.