【摘要】 以往研究针对三维内裂纹在单轴拉伸下的裂纹扩展与三维内裂纹尖端的应力强度因子变化较少,为定量化研究三维内裂纹单轴拉伸下的裂纹扩展与应力强度因子的变化,对不同预制内裂纹角度在拉伸荷载作用下的裂纹扩展规律进行了数值模拟研究,将裂纹扩展过程及最终破坏形态与已有研究进行了对比。计算结果表明:当预制裂纹角度为0°时,预制裂纹呈现自相似扩展,当预制裂纹为其他角度时,预制裂纹尖端出现翼裂纹扩展,预制裂纹角度为15°、30°、45°、60°时,翼裂纹与原预制裂纹分别呈18°、49°、64°与80°;随着预制裂纹与水平方向的角度增大,Ⅰ型应力强度因子逐渐减小,对于同一预制裂纹角度来说,预制裂纹短轴顶点上的Ⅰ型应力强度因子较其他方向要大;随着预制裂纹角度的增大,Ⅱ型应力强度因子整体上先增大后减小;对于同一种预制裂纹角度来说,预制裂纹的左端与右端(对应于距离为0,0. 5,1处)Ⅱ型应力强度因子达到最大,而预制裂纹短轴处顶点(对应于距离为0. 25和0. 75处)Ⅱ型应力强度因子达到最小为0;数值模拟结果与室内试验结果体现出较好的一致性。研究成果为正确认识轴拉情况下的三维裂纹扩展规律提供了一定的参考。更多还原

【Abstract】 The crack propagation of three-dimensional internal crack under tensile load has been a difficult and hot problem in geotechnical engineering. In order to quantitatively explore the crack propagation and the change of stress intensity factor of standard cubic specimen with three-dimensional internal crack under uniaxial tensile load,the variation of the crack propagation law of different prefabricated internal crack angles under tensile load was simulated numerically,and the crack propagation process and the final failure morphology were compared with the existing research. The results showed that the precast cracks exhibit self-similar propagation when the precast crack angle is 0 degree and when the precast cracks are at other angles,the wing crack propagates at the tip of the precast crack. When the angle of the precast crack is 15 degrees,30 degrees,45 degrees,60 degrees,the wing crack and the original precast crack present an angle of 18 degrees,49 degrees,64 degrees and 80 degrees. With the increase of the angle between the precast crack and the horizontal direction,the relative stress intensity factor of mode I decreases gradually,and for the same prefabricated crack angle,the relative mode Ⅰ stress intensity factor on the short axis vertex of prefabricated crack is larger than that in other directions. For the mode Ⅱ stress intensity factor,the relative mode Ⅱ stress intensity factor increases first and then decreases with the increase of the prefabricated crack angle. For the same precast crack angle,the left and right end of the precast crack( corresponding to the distance of 0/0. 5/1) reaches the maximum for the mode II stress intensity factor,while the relative II type stress intensity factor of the vertex of the short axis of the precast crack( corresponding to the distance of 0/0. 5/1) reaches the minimum of 0 at 0. 25,0. 75,and the numerical simulation results are in agreement with the laboratory test results. The research results provide a certain reference for the correct understanding of the three-dimensional crack propagation law under the condition of axial tension.更多还原