Investigation of fracture and fatigue in a metal/polymer composite

This paper presents the results of a combined experimental and analytical study of the fatigue and fracture behavior of a polymer/metal composite that was developed recently for self-lubricating applications in automotive engines that utilize liquefied natural gas as fuel. For comparison, the microstructure and the fatigue and fracture behavior of a non-polymer containing 'matrix' material are also presented. Since the crack profiles observed in both systems under monotonic or cyclic loading reveal significant components of ligament bridging, micromechanics models are presented for the modeling of crack bridging. The resulting predictions of resistance-curve behavior are compared with measured resistance curves. The shielding effects of ligament bridging are also quantified under cyclic loading. The implications of the work are also discussed for the modeling of fatigue damage and fracture in polymer/metal coatings.