三维表面裂纹相互作用扩展贯通机制试验研究

EXPERIMENTAL STUDY ON PROPAGATION AND COALESCENCE MECHANISMS OF 3D SURFACE CRACKS

通过对用机械法预制多个硬币状裂纹的冷冻有机玻璃材料进行单轴加载系列试验,研究脆性材料三维表面裂纹扩展演化和贯通机制。研究结果表明,三维裂纹间的相互作用对裂纹萌生和扩展主要有两种影响,即相互促进或彼此抑制,裂纹演化过程中其空间位置起主要作用。三维表面裂纹间的贯通要复杂得多,同时受裂纹切割深度、空间位置影响较大。这一研究加深了对有机玻璃材料(PMMA)等透明脆性材料破坏机制的了解,同时对岩石材料破坏机制的研究也大有裨益。

A series of uniaxial compressive tests on the frozen PMMA with pre-existing 3D cracks were performed in laboratory to investigate the mechanisms of crack propagation and coalescence in brittle materials. It is found that for 3D surface cracks, the interactions of cracks affect crack growth and extension in two aspects, i.e. the interaction either prompting crack extension or restraining it. The mechanism of crack interaction depends mainly on the location of cracks in spatial domain. The propagation and coalescence of 3D surface cracks are dependent on the crack depth and the crack configuration. The test results are helpful to more understanding of the failure mechanism of brittle materials including PMMA and also to the study of the failure mechanism of rock under loading.