2013 Timoshenko Medal Award Paper—Completion and Closure on Failure Criteria for Unidirectional Fiber Composite Materials

Building upon previous work, the failure criterion for unidirectional fiber composite materials is examined using a sensitivity analysis as applied to its transverse, matrix controlled failure properties. A new and general relationship is found between these three properties thereby reducing the total number of independent properties needed to calibrate the theory to five. This completes and closes the development of failure criteria for unidirectional fiber composites by the polynomial invariants method. A broad but detailed evaluation of the resulting failure criteria is given. Future applications for these new failure criteria are discussed.

Effective Thermoelastic Moduli of a Unidirectional Fiber Composite Containing Interfacial Arc Microcracks

In this work, we have employed a variational model to examine the effect of fiber-matrix debonding on the thermoelastic response of a unidirectional composite. The model is designed to represent the concentric cylinder model of a composite representative volume element and it contains the capability to enhance the accuracy of a given numerical solution. The effect of the extent of debonding as well as fiber volume fraction on all the effective moduli of the unidirectional composite has been examined. Numerical results reported in the literature are compared with the results of the model developed in the present study to examine the quality of the model.