Abstract
This paper investigates the crack interaction, initiation, and propagation rules of rock-like materials containing two collinear cracks. Based on the Kachanov method, the formulations for stress intensity factors (SIFs) of two collinear cracks and two winged cracks are derived, respectively. The influences of bridge ligament and crack length on the crack interaction are analyzed theoretically. The results show that the propagation of a long crack is independent of crack interaction when d≥a2 and the same rule applies for a short crack when d≥a1. With the growth of wing cracks, the SIF of wings first remarkably decreases and then it tends toward a steady value. Subsequently, the propagation of collinear cracks and cracking processes under uniaxial compression are analyzed experimentally and numerically. Both the experimental results and simulation results demonstrate that shear cracks tend to initiate and propagate at higher inclination angle. The crack coalescence is affected by the inclination angle of bridge ligament. For increasing the inclination angle, the crack coalescence varies from wing crack failure to shear crack coalescence. As bridge ligament increases, the crack coalescence varies from shear crack coalescence to shear-wing crack coalescence and then to wing crack failure.
Highlights
Rock and rock-like materials usually contain a number of cracks, which affect the physical properties and influence the failure patterns of the rock material
In order to improve the understanding of fracture mechanism of brittle materials with multiple cracks, abundant theoretical and experimental studies have been conducted on rock materials containing two cracks [2,3,4]
E interaction of cracks can significantly accelerate the speed of rock failure. e previous work provides a good understanding of the effect of interaction on mechanical properties. e experimental studies on rock-like materials containing cracks indicate that the geometry of the preexisting cracks, such as crack inclination angle, bridge ligament angle, and crack aperture have a strong influence on strength [2, 4, 19], coalescence behavior [3, 20,21,22], and fatigue life of the structural component [23, 24]
Summary
Rock and rock-like materials usually contain a number of cracks, which affect the physical properties and influence the failure patterns of the rock material. In order to improve the understanding of fracture mechanism of brittle materials with multiple cracks, abundant theoretical and experimental studies have been conducted on rock materials containing two cracks [2,3,4]. Considerable progresses have been made for stress intensity factors determination of multiple cracks, to accurately describe the effect of the crack interaction on the failure. E experimental studies on rock-like materials containing cracks indicate that the geometry of the preexisting cracks, such as crack inclination angle, bridge ligament angle, and crack aperture have a strong influence on strength [2, 4, 19], coalescence behavior [3, 20,21,22], and fatigue life of the structural component [23, 24]. The influences of inclination angle and bridge ligament on cracking are explored
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