3D Kink Cracked Version crack#
In addition, the excellent transparency of such material makes it possible to observe the crack propagation inside the material.
3D Kink Cracked Version free#
The adopted 3D printing material is resin consisting of a rapidly curing epoxy prototype compound, which is brittle and linearly elastic under freezing conditions and is free of residual stress. The 3D printing technology has advantages over the above traditional manufacturing methods for its efficiency, accuracy, and repeatability. The traditional methods for producing prefabricated fissures include inserting a sample with a mica sheet or a steel sheet and cutting by a water-jet machine or high-precision electric cutting machine. The experimental materials can be categorized into rock-like materials and actual rock materials. However, for intermittent non-straight fissures, especially the effect of the interaction between intermittent K–S fissures (a kinked fissure and a straight fissure) on their behavior patterns in cracking, the propagation and coalescence behaviors under experimental conditions have not yet been sufficiently discussed. It was found that the decrease of strength is accompanied by the internal crack at the stage of crack growth and propagation, following the occurrence of the external crack, at relatively large flaw and ligament angles. Double S-shaped fissures in natural marble specimens were investigated by Dong et al. , whose results have shown that the tensile crack propagation of wing cracks is the major type of failure of kinked fissures under the uniaxial compression experiments. A single kinked fissure was also investigated by Ma et al. It was found that the effective curvature has a strong influence on the crack initial position. performed uniaxial compression experiments on straight (S)-shaped fissures. quantified the fatigue crack growth rate of periodic kinked cracks and made a comparison with that of ordinary cracks, which suggested that the kinked rate decreases as the kinked angle increases, and the fatigue cracks propagated, whose velocity is related to the kinked angle and the crack length. proposed crack retardation equations to numerically estimate the crack path and associated stress intensity factors of kinked and bifurcated cracks. performed a compression test on a cracked marble sample containing prefabricated circular holes and concluded that the direction and geometry of the cracks determine where the secondary cracks will occur. Isida and Noguchi gave a reliable formula for the stress intensity factors of various branch cracks and calculated the stress intensity factors of all the branches and the main crack tip. In the past, some scholars have also performed theoretical and experimental research on non-straight fissures.
Figure 1 shows a natural granodiorite sample under CT scanning, where many non-straight fissures can be observed. Non-straight fissures extensively exist in natural environments. performed a triaxial compression test on a sandstone sample containing two preexisting 3D defects, which showed shear crack coalescence in the ligament region and identified indirect coalescence outside the ligament region. conducted triaxial compression tests on samples with two closed non-overlapping flaws and found that the arrangement of the flaw pair had a more significant influence on the rock deformation, rock strength, and crack combination mode than the confining pressure.
The two-fissure cases have been experimentally studied by Wong and Einstein, whose results indicated that the fissure inclination angle, bridging angle, and ligament length have a strong influence on the crack coalescence. Sagong and Bobet carried out compression experiments on samples containing two to 16 fissures, and the results indicated that the crack propagation in the multiple-fissure samples was similar to those that contained two fissures. Some previous experiments have investigated the failure characteristics of brittle materials with multiple straight fissures.
0 kommentar(er)
