Measurement and analysis of stress transfer and toughness at a fiber-matrix interface

The finite element method is used to investigate the axial fiber stress profiles and energy changes accompanying interfacial debonding and/or matrix cracking following a single fiber fragmentation event. Since the stress transfer along the fiber length changes over a long distance from the broken fiber end, a study was made of the effect of model size and material properties on calculated values of the stress profiles and energy changes. The radial dimension must extend to at least 10 fiber diameters and the half-fragment length must also be greater than approximately 20 fiber diameters, before a size independent calculated value of the strain energy release rate, G, can be attained. Some of the static-elastic analysis limitations, i.e. the elastoplastic behavior of the matrix, the transient dynamic events following filament fracture, and the frictional effects are also discussed. © 1998 Published by Elsevier Science Ltd. All rights reserved.