Analyses of the Micromechanics of Stress Transfer in Single Fiber Pull-Out Tests

Abstract

Fiber composite technology is based on taking advantage of the high strength and high stiffness of fibers, which are combined with matrix materials of similar/ dissimilar natures in various ways, creating inevitable interfaces. In fiber composites, both the fiber and the matrix retain their original physical and chemical identities, yet together they produce a combination of mechanical properties that cannot be achieved with either of the constituents acting alone, due to the presence of an interface between these two constituents. Fibre-matrix interface is known to have contribution to the mechanical performance of fibre-reinforced composite by its potential for load transfer between the fibre and the matrix. The understanding of the interface (or interphase) in composites is the central point of this interdisciplinary effort. In this work, we are interested in the qualitative study of the interface by the means of’ a micromechanical test, which defined by a behavior of a fiber embedded in a matrix block (test pull-out) to characterize the fiber/matrix interfacial adhesion solicited in traction. Initially, a theoretical study of the test is highlighted. Equations which give the evolution of the normal constraints to the level of the enchased filament and the sheath of matrix surrounding it, as well as the shear stress on the level of the interface are presented. In second place, we have to carry out a simulation of the mathematical equations under Matlab by varying the various parameters which present an influencing on the value of the interfacial shear stress, such as, the geometry of the model, embedded length of the fiber, fiber diameter and loading conditions, including components (fiber, matrix, interface). Curves are plotted and of interpretations are presented.