A statistical model of fatigue damage evolution in particulate‐reinforced metal‐matrix‐composites

Abstract

A statistical model of fatigue damage evolution has been developed for particulate‐reinforced metal‐matrix‐composites (MMCs) by taking into considerations both the initial damage distribution and the effect of particulate reinforcement on fatigue damage development. The growth of microscopically fatigue‐damaged regions in particulate‐reinforced MMCs is considered as a stochastic process, and both the non‐equilibrium statistical method and minimum strength principle are used to establish the evolution equation of fatigue damage. The fatigue damage evolution equation developed in the present study characterizes not only the kinetic process of fatigue damage evolution but also sets up the relationship between the mechanism of fatigue damage growth of the microscopically damaged regions and the result of fatigue damage, i.e. degradation of mechanical properties of particulate‐reinforced MMCs. A new expression for calculating the cumulative fatigue damage and a new formula for predicting the average fatigue strength of the particulate‐reinforced MMCs are derived. Experimental data of 2080Al/SiCp composites are analysed and compared with results obtained with the present model. It is shown that the experimental results can be described well by the calculations.

Mechanics of Random and Multiscale Microstructures

“…Metallic matrix composite materials may constitute an exception to this rule, as indicated in the following, since in these materials the interaction of the fatigue damage development and reinforcing particles, which gives rise to various damage development mechanisms such as crack deflection, crack trapping and bridging, plays a key role (see e.g., [Ding et al, 2000]). In the present part an attempt is made to identify the physical sources for the existence of this scatter and to show how this scatter can be modelled from a knowledge of the fatigue damage micromechanisms.…”