Failure Criteria for Fibrous Anisotropic Materials

Abstract

A general failure criterion for fibrous anisotropic materials is developed in the paper. Since the strength of a lamina should depend on the lamina angle and be symmetric with respect to this angle, the strength of an off‐axis lamina may be expressed as a cosine series. The criterion has the flexibility of any desired degree of accuracy. This capability is needed for complicated materials such as wood and composites. Hankinson's empirical formula for uniaxial loading can be derived by using only the first two terms of the present approach. The accuracy of the criterion is justified through the comparison with experimental data for several material systems subjected to uniaxial and combined loading. The present criterion is also compared with other criteria as well and results are presented in figures. One of the main features of this criterion is that it does not need the shear strength of a material, which is difficult to determine experimentally.