论文部分内容阅读
采用一种含中心直裂纹的混凝土圆盘试件,对其进行准静态径向压缩测试,通过改变中心裂纹倾角和混凝土的配比,得到了不同情况下混凝土试件的裂纹初始扩展角和断裂阻力.基于Ayatollahi等人修正的最大切向应力准则(MMTS),通过联立理论公式求解得到不同配比、不同裂纹形式(II型和I-II混合型)混凝土试件的裂纹初始扩展角和断裂阻力的预测值,并将其与实验值进行了比较分析.其中MMTS准则是同时考虑了裂纹尖端应力场中奇异项和非奇异项(即Williams级数展开项中的T应力、A3和B3阶项,并忽略了更高阶项)的最大切向应力准则,使用超确定有限元法(FEOD)对Williams级数展开项的无量纲参数进行计算,并采用考虑了A3阶项的Schmidt模型计算断裂过程区的大小.研究结果表明,与传统MTS准则、GMTS准则相比,MMTS准则能够更好地预测混凝土试件裂纹初始扩展角和断裂阻力,特别是针对II型载荷占主导地位时的情况.
A test specimen of concrete disc with central straight crack was used to perform quasi-static radial compression test. The initial crack propagation angle and fracture of concrete specimens under different conditions were obtained by changing the center crack dip angle and the concrete mix ratio Resistance.According to the maximum tangential stress criterion (MMTS) revised by Ayatollahi et al, the initial crack propagation angle of concrete specimens with different proportions and different crack types (mixed type II and I-II) was solved by the simultaneous theoretical formula And the predicted values of fracture resistance are compared with those of the experimental data.The MMTS criterion considers both the singular and the non-singular terms in the crack tip stress field (ie, the T stresses in the Williams series expansion terms, A3 and B3 Order terms and ignoring higher-order terms, the dimensionless parameters of the Williams series expansion are calculated using the FEOD method, and the Schmidt model considering the A3-order term Calculated the size of the fracture process area.The results show that, compared with the traditional MTS criteria, GMTS criterion, MMTS criterion can better predict the initial expansion angle and fracture resistance of concrete specimens crack, especially for Type II loads dominate the situation.