%0 Journal Article %A Tandon, G. P. %A Kim, Ran Y. %A Bechel, Vernon T. %D 2004 %I Begell House %N 1 %P 13 %R 10.1615/IntJMultCompEng.v2.i1.70 %T Construction of the Fiber-Matrix Interfacial Failure Envelope in a Polymer Matrix Composite %U https://www.dl.begellhouse.com/journals/61fd1b191cf7e96f,043f5ff560b33d1e,4e0993654c7ec924.html %V 2 %X Previous research efforts have used the single-fiber cruciform test to measure the tensile normal strength of a fiber/matrix interface while eliminating the influence of free-edge stresses that are present in transverse testing of conventional straight-sided specimens. In this work, the cruciform specimen was modified to characterize the fiber/matrix interface strength under combined transverse and shear loading. Initiation and growth of interface debonds were detected optically by observation of variations in the intensity of light reflected from the surface of the fiber during loading. Test data reduction was accomplished with a 3-D finite element model of the angled cruciform sample. Using the measured value of applied stress at debond initiation, and the calculated stress concentration factors at the fiber/matrix interface, a mixed-mode failure envelope was constructed in the normal-shear stress space, and a quadratic failure criteria was proposed. Finally, a brief discussion has been included of how this interfacial strength data may be used in ysis to predict bulk characteristics of a composite laminate. %8 2004-03-01