Experimental characterization of in-plane debonding at fiber-matrix interface using single glass macro fiber samples

Fiber-matrix interface debonding is investigated using a hybrid experimental-computational approach. Model composite specimens are prepared using a single glass macro fiber embedded in an epoxy test piece and then subjected to uniaxial tension. Displacement and strain fields developed in the vicinity of the fiber-matrix interface are measured experimentally using optical digital image correlation. Debonding initiation and propagation stages are characterized using the transient strain evolutions at the fiber-matrix interface. Correlations between local and global stresses are identified by combining full-field measurement data and analytical solutions. Local deformation data obtained experimentally is then used to identify a stress-based traction-separation model. Experimental measurements are verified and supplemented by finite element analyses. Sources of uncertainty and the limitations associated with the proposed hybrid approach are discussed. The approach presented herein provides a systematic methodology for the quantification of the mechanics and failure at the fiber-matrix interfaces in unidirectional composites under transverse loading conditions.