混凝土三维裂缝的非线性数值分析

Nonlinear numerical analysis of three dimension crack in concrete

对各种断裂类型的Ｐ－Δ试验全曲线进行处理后，拟合得到了各σ－ｗ软化曲线的统一数学表达式，以及相应的应力－应变本构关系．同时从能量的观点出发，将应力－应变本构关系转化为能量－应变本构关系，从而可以方便地跟踪三维裂缝的扩展过程．用自编的非线性有限元程序成功地数值模拟了三点弯曲梁的裂缝扩展过程。

The formula of the σ w softening curve has been fitted by dealing with all types of P Δ curves, and the σ ε constitutive relation has been obtained. By using energy theory, the σ ε constitutive relation can be turned into the energy strain constitutive relation, thus, the process of crack propagation into three dimensions can be tracked conveniently. The process of crack propagation of three point bending beam has been numerically simulated successfully with the program of nonlinear FEM, and the P Δ curve conforms to measured curve.