砂岩类脆性无序介质连续破坏过程的细观模拟

为了分析砂岩类无序介质在各种荷载作用下的连续破坏过程,本文提出了梁-颗粒细观模型。在此模型中,介质被离散为一系列的颗粒单元,这些颗粒单元均由弹脆性的梁单元联结。颗粒的力学行为由离散单元法和有限单元法确定。当某个梁单元所受应力超过其强度时,就随即将它从计算网络中剔除,以模拟介质的破坏行为。为了验证数值模型的可靠性,分别从破坏模式和荷载-位移曲线两方面与物理模型实验进行了对比,结果表明两者基本一致。此外,探讨了无序性对介质裂纹分布形式的影响,并用分维表述了裂纹分布与荷载强度之间的内在联系。 

MODELLING OF PROGRESSIVE FAILURE OF BRITTLE DISORDERED MATERIALS E. G. SANDSTONE

In this paper the beam-particle model at a fine structural scale is presented for analysis of the progressive failure of such brittle disordered materials as sandstone by diffe rent loadings.In the model,the media are divided as an assembly of particle elements linked by elastic brittle beam elements.The mechanical behaviour of particle elements is determined by the distinct element method and finite element method.As soon as a particular beam element is stressed beyond its assigned strength it is removed from the computation in simulation of the rupturing of the material.Two physical experiments are performed to verify the numerical results.The rupturing model and load-displacement response obtained are in good agreement with the experimental results.Moreover,the influence of heterogeneity on fracture patterns is also discussed and the correlation between the fracture distribution and the loads imposed is characterized in fractal dimensions.