Comparison of the stress transfer in single- and multi-fiber composite pull-out tests

Analyses of the elastic stress transfer taking place across the fiber-matrix interface are presented for single- and multi-fiber composite pull-out tests. The multi-fiber composite is treated as a three-cylinder assemblage consisting of a central fiber, a matrix annulus, and a composite medium. The forms of the fiber axial stress and the interface shear stress distributions along the embedded fiber length are determined for single- and multi-fiber composite pull-out tests and their dependences on the fiber volume fraction, the dimensions of the specimen, the fiber-to-matrix modulus ratio, and the embedded fiber aspect ratio are displayed. The stress transfer for a perfectly bonded interface for the two pull-out tests is compared and the difference is clearly shown. In addition, for the single-fiber composite pull-out test, the present theory is compared with some existing theories.