不同夹角Y型裂纹混凝土试样破坏特征的研究

本文对含非对称Y型分支裂纹混凝土试样在三向压缩载荷下的破坏特征进行了研究，利用ABAQUS软件进行了数值计算，并与试验结果进行了对比分析。试验和数值计算结果均表明: 随着分支裂纹与主裂纹之间夹角由小到大的变化，分支裂纹尖端的应力强度因子KI从负值变化到正值，而两个水平主裂纹尖端的应力强度因子KI的绝对值都在增加。但对KII而言，分支裂纹的应力强度因子KII先减小后增加，并在30°～45°之间出现极值。通过KImax随角度变化的曲线可知，当倾角为75°时试件的抗压强度最低，当倾角为90°时的强度次之，与试验基本吻合。

Investigation into Effect of Y-shaped Crack Angles on Strength of Plain Concrete

According to fracture mechanics theory, cracks enormously affect the strength of materials with their diverse forms. This paper investigated the response of concrete specimens with asymmetrical Y-shaped crack under triaxial compression. Tests were also simulated using ABAQUS to get a comparison. Both tests and simulation show that when the angle between branch crack and stem crack changes from 15° to 90°, the stress intensity factor KI of crack tip of C changes from negative value to positive value, while those of crack A and crack B keep increasing in absolute value. As to KII, however, the stress intensity factor of crack C decreases first, then increases, and its peak value appears between 30° and 45°. From curve of KImax against angle we can see that the strength reaches its minimum value at 75°,and that at 90° follows, which resembles the tests.