Effect of Frequency on Fatigue Crack Propagation in Short-Glass-Fiber-Reinforced Nylon 66.

摘要

The fatigue crack propagation (FCP) response of nylon 66 and composites containing 16 and 31 vol. % short glass fibers was determined at frequencies of 1, 10, 50, and 100 Hz. The sensitivity to frequency was found to depend on glass content and, in the case of the pure matrix, on the value of the stress intensity factor range, delta K. Whereas both glass-reinforced compositions were superior to the pure matrix material, an inversion in relative ranking of the former occurred as the cyclic frequency was changed. Also, the strong frequency sensitivity revealed by nylon 66 at low delta K values disagrees with results reported previously. To explain these phenomena a concept based on the competition between localized and more generalized heating is proposed. (Author)