FINITE-ELEMENT SIMULATIONS OF FIBER PULL-OUT

Fiber pull-out is simulated through a quasi-static analysis of a circular elastic cylinder with a rigid cylindrical fiber embedded in its center. The interface between the fiber and the matrix is characterized in terms of a rate dependent internal variable friction constitutive relation. The analysis is carried out in two steps; one simulating the residual stresses that develop while cooling the cylinder from its processing temperature and the other simulating the mechanical response during fiber pull-out. Depending on parameter values, fiber pull-out can occur smoothly or a stick-slip instability can occur. Numerical simulations of fiber pull-out are presented that explore the effects of loading device stiffness, loading rate, and friction law parameters on the predicted behavior. For example, the amplitude of the load fluctuations during stick-slip was found to decrease as the rate of pull-out increased.