Measurement of shear lag parameter β for a fibre bundle pull-out geometry

Shear-lag models are commonly used to describe the distribution of shear stresses along the loaded fibre/matrix interface in fibre reinforced composites. In this work the shear-lag model is extended to the specific geometry and boundary conditions of a fibre-bundle pull-out test. A new experimental procedure is presented to determine the shear-lag parameter β. The method is based on purely mechanical data, i.e. load–displacement curves at specific points of the specimen. Results are given for a bidirectionally woven carbon/carbon composite, but the test procedure can be applied for any other endless fibre-reinforced material.