Abstract
In this paper, the interactions between two parallel cracks are investigated experimentally and numerically. Finite element models have been established to obtain the stress intensity factors and stress distributions of the parallel cracks with different positions and sizes. Fatigue crack growth tests of 304 stainless steel specimens with the single crack and two parallel cracks have been conducted to confirm the numerical results. The numerical analysis results indicate that the interactions between the two parallel cracks have an enhancement or shielding effect on the stress intensity factors, depending on the relative positions of the cracks. The criterion diagram to determine the enhancement or shielding effect between two parallel cracks is obtained. The changes of the stress fields around the cracks have been studied to explain the mechanism of crack interactions.
Highlights
Fatigue damage of ships, aircrafts, pressure vessels, and other engineering components will be caused by fluctuation loadings during their service time [1]
The accumulation of the fatigue damage of engineering components leads to fatigue cracks [2]
Ma et al [7] studied the interactions between an edge and an embedded parallel crack, and they found that the normal and deviation distances as well as the relative crack sizes could affect the value of the stress intensity factors of the two cracks
Summary
Aircrafts, pressure vessels, and other engineering components will be caused by fluctuation loadings during their service time [1]. Previous studies have investigated multiple crack interactions and their effects on the stress intensity factor [5,6,7,8,9,10,11,12,13,14]. Jiang et al [9] studied two unequal parallel cracks in a finite width plate subjected to a remote tensile load. They found that because of the crack interactions, the stress intensity factors at the tips of two cracks simultaneously decreased. An empirical formula was Materials 2019, 12, 1331; doi:10.3390/ma12081331 www.mdpi.com/journal/materials
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