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岩石在承载之初,由于微缺陷无序成核和有限生长,在材料内部形成大量分布性微裂纹。在该文中,这种演化机制被归结为:微缺陷随机、孤立成核生成最小微裂纹和微缺陷无重叠聚集成核、排列生长形成大尺度微裂纹,裂纹尺度生长是微缺陷成核数的函数。利用微裂纹尺度-频数分布分形以及微裂纹粗糙表面分形,建立基于微缺陷累计成核数序列的裂纹尺度生长模型和损伤演化模型。通过对二维岩石试件破坏过程的微裂纹尺度统计和损伤测试表明,模型的预测结果与观测值符合较好。由于微缺陷成核与声发射源机制具有相似性以及微缺陷成核数序列与声发射数序列具有相似性,所以该模型可用于通过声发射参数序列跟踪微裂纹生长和损伤演化。裂纹尺度生长对于完整认识材料宏观力学性质演化和预测材料灾变具有重要意义。
At the beginning of bearing, the rock formed a large number of distributed microcracks inside the material due to the disordered disordered nucleation and limited growth. In this paper, the evolution mechanism is summarized as: micro-defects random, isolated nucleation to produce the smallest microcracks and micro-defects non-overlapping aggregation nucleation, growth and formation of large-scale micro-cracks, crack growth scale micro-defect nucleation function. Based on the fractal scale of microcrack - fractal distribution and the fractal of the rough surface of microcracks, a crack growth model and a damage evolution model based on the accumulated nucleation number sequence of micro - defects were established. Based on the statistics and damage tests of the microcracks in the failure process of two-dimensional rock specimens, the prediction results of the two models agree well with the observed values. Due to the similarities between micro-defect nucleation and acoustic emission source mechanism and the similarities between micro-defect nucleation sequence and acoustic emission sequence, this model can be used to track the growth and damage evolution of microcracks through acoustic emission parameter sequence. Crack-scale growth is of great importance for the complete understanding of the macroscopic mechanical properties of material and the prediction of material catastrophe.