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采用FLAC模拟了混凝土梁三点弯曲条件下的破坏过程,其中考虑了抗拉强度及峰值后软化曲线非均质性,得到了梁的载荷-CMOD曲线、梁跨中横截面上的水平方向应力及塑性拉伸应变的分布规律、应变软化区域及真实裂纹长度的变化规律、拉伸破坏单元及真实裂纹的发展规律。结果显示载荷-CMOD曲线的数值结果与C40混凝土的实验结果基本吻合。考虑抗拉强度及峰值后软化曲线的非均质性之后,真实裂纹多点启动。一些真实裂纹出现之后,发生聚合,同时,新的真实裂纹启动。在峰值后,随着CMOD的增加,应变软化区域长度的增加速度变缓。当真实裂纹出现之后,应变软化区域的长度基本保持不变。随着CMOD的增加,首先,梁绕跨中横截面没有转动;之后,梁绕跨中横截面的转角基本保持不变;随后,梁绕跨中横截面的转角变得越来越大。拉应变局部化区的厚度大致等于3个―4个单元的长度。
FLAC was used to simulate the failure process of concrete beams under three-point bending. The tensile strength and peak softening curve were taken into account. The beam load-CMOD curve, the horizontal stress And plastic tensile strain distribution, strain softening region and the real crack length changes, the development of tensile failure unit and the real crack. The results show that the numerical results of the load-CMC curve are in good agreement with the experimental results of C40 concrete. Taking into account the tensile strength and peak after the softening curve of the heterogeneity, the real crack more start. Some real cracks occur after the polymerization occurs, at the same time, the new real crack starts. After the peak, with the increase of CMOD, the length of strain softening region increases slowly. When the real crack appears, the length of strain softening area remains unchanged. With the increase of CMOD, firstly, the cross section of the beam around the mid-span does not rotate; after that, the angle of the cross-section of the mid-span of the beam around the mid-section remains substantially unchanged; The thickness of the tensile strain localized zone is approximately equal to the length of 3 to 4 units.