应用修正的虚裂纹模型研究混凝土结构的三维裂缝扩展

本文在虚裂纹模型中引入初裂强度因子的概念以研究混凝土结构的三维裂缝扩展。虚裂纹的扩展由裂纹尖端的初裂强度因子和虚裂纹所传递的软化应力共同控制。将软化应力分析曲线分段线性化进行模拟,这使问题得到很大程度的简化,同时又保证了解的必要精度。对所建立的有限元基本方程组建议了一次性的求解方法,可以不进行迭代,这既保持了解的稳定,又减轻了计算工作量。

Studies of Three Dimensional Crack Propagation in Concrete Structures Based on Modified Ficticious Crack Model

A concept of initial stress intensity factor is introduced in the ficticious crack model for the studies of three dimensional crack propagation in concrete structures. The extension of the ficticious crack is controlled by both the initial stress intensity factor at the crack tip and the softened stresses transmitted through the ficticious crack. The distribution of the softened stresses along the surface of the ficticious crack is approximated by a segmented line which simplifies the problem to a great extent while ensures the necessary precision of the solution. A direct approach for solving the basic equations of finite element analysis is suggested, as no iteration is needed, the stable solution is achieved, moreover , the computational efforts can also be reduced.