全级配混凝土梁弯拉应力—应变全曲线的细观力学模拟

Meso-mechanical Simulation on the Total Stress-strain Curve of Fully-graded Concrete Beam in Bending

为了测定全级配混凝土梁的抗弯强度,采用位移控制的加载有限元程序模拟了全级配混凝土梁的弯拉实验,得到了相应的弯曲拉伸应力-应变全曲线。数值模拟得到的梁的极限荷载、抗弯强度与试验结果基本吻合。数值模拟结果还表明,四级配混凝土梁的极限荷载高于三级配混凝土梁,但是抗弯强度低于三级配混凝土。梁的最终破坏表现为一条主裂缝贯通混凝土梁的横截面,表现出较强的拉应变软化现象和局部化现象。

In order to evaluate the flexural strength of fully-graded concrete, the bending-tension test of fully-graded concrete beam were simulated using displacement-controlled FEM, the corresponding total stress-strain curve was got. The ultimate loads and the flexural strengths got from numerical simulation agree well with the experimental data. The results of simulation showed that the ultimate load of four-graded concrete is greater than three-graded concrete＇s; the flexural strength of the former is smaller than that of the latter. The ultimate failure forms of beam was that one main crack penetrated the cross section. It reveals the phenomenon of tensile strain softening and localization.