混凝土Ⅰ-Ⅱ型复合裂纹应力强度因子的探讨

混凝土结构断裂破坏的应力强度因子研究是领域近几十年来一个十分重要的内容。本文阐述了基于Irwin的Ⅰ-Ⅱ型复合裂纹断裂应力强度因子计算,讨论了断裂过程的混凝土复合型断裂周向应力判据,与试验机模拟软件结果对比认为低强度的混凝土的应力场较为符合KⅠ和KⅡ之间的规律。

The asymptotic field of mode Ⅰ quasi-static crack growth on the interface between a rigid and a pressure-sensitive material

A mechanical model of the quasi-static interface of a mode I crack between a rigid and a pressure-sensitive viscoelastic material was established to investigate the mechanical characteristic of ship-building engineering hi-materials. In the stable growth stage, stress and strain have the same singularity, ie （σ, ε） ∝ r^-1/（n-1）. The variable-separable asymptotic solutions of stress and strain at the crack tip were obtained by adopting Airy＇s stress function and the numerical results of stress and strain in the crack-tip field were obtained by the shooting method. The results showed that the near-tip fields are mainly governed by the power-hardening exponent n and the Poisson ratio v of the pressure-sensitive material. The fracture criterion of mode I quasi-static crack growth in pressure-sensitive materials, according to the asymptotic analyses of the crack-tip field, can be viewed from the perspective of strain.

压电压磁双层材料界面裂纹断裂特性进一步分析

该文利用积分变换和奇异积分方程技术研究压电压磁双材料界面裂纹在磁导、电位移和机械载荷作用下的二维断裂问题。本文仅考虑四种理想的裂纹面电磁边界条件即磁电不导通(情形1)、磁导通电不导通(情形2)、磁不导通电导通(情形3)和磁电导通(情形4)。导出了应力强度因子(SIF)和能量释放率(ERR)的表达式,给出了ERR的大量数值结果,并与已有结果进行了对比。研究成果对压电压磁多层复合结构的设计具有理论与应用价值。