基于能量耗散原理的类岩石材料损伤演化试验研究和数值模拟

发布时间：2019-04-07 19:42

【摘要】：在外荷载、环境的作用下,由于微观结构的缺陷(如细微裂纹、孔洞等)引起的材料或结构的劣化过程,叫做损伤。由于裂隙的存在会对岩体工程的强度、变形和寿命等构成重大的威胁,因此研究裂隙岩体的损伤演化对于工程和科研都有十分重要的价值。本文分别采用试验和数值计算的方法对预制裂纹试样进行单轴压缩试验和数值模拟,从不同裂纹布置下的试样损伤演化规律分析裂纹布置影响因素在其中的影响。本文通过对预制单(双)裂纹试样进行单轴压缩试验,应用基于能量耗散理论的损伤变量定义对加载全过程的应力应变曲线进行分析,对裂纹长度、裂纹倾角、裂纹厚度和岩桥倾角等因素对试样和模型的损伤及损伤演化过程的影响进行分析。试验结果表明：预制裂纹会使含预制裂纹试样的损伤较完整试样有较大的增加；在单轴压缩荷载下,含预制裂纹试样的损伤演化随着裂纹布置的不同而产生不同程度的差异；试样的损伤演化规律与其断裂模式联系密切。应用基于ABAQUS有限元程序的损伤塑性模型,对含预制单裂纹模型进行数值计算。计算结果表明：拉伸损伤始终大于压缩损伤,即由于拉伸产生的翼型裂纹的出现可以作为裂纹起裂的标志；随着裂纹厚度的增大,裂尖压缩损伤和裂尖拉伸损伤均逐渐减小,而随着裂纹长度的增大,裂尖压缩损伤和裂尖拉伸损伤均逐渐增大；起裂角随着裂纹倾角增长的速度明显大于其随着裂纹厚度和裂纹长度增长的速度。
[Abstract]:Under the action of external load and environment, the deterioration process of material or structure caused by microstructure defects (such as micro-cracks, holes, etc.) is called damage. Because the existence of cracks will pose a great threat to the strength, deformation and life of rock mass engineering, it is very important for engineering and scientific research to study the damage evolution of fractured rock mass. In this paper, the uniaxial compression test and numerical simulation of prefabricated crack specimen are carried out by means of test and numerical calculation, respectively. The influence factors of crack layout are analyzed from the damage evolution rule of specimen under different crack arrangement. In this paper, through uniaxial compression test of prefabricated uniaxial (double) crack specimen, the stress-strain curve of the whole loading process is analyzed by using the definition of damage variable based on energy dissipation theory, and the crack length and crack inclination are analyzed. The effects of crack thickness and rock bridge inclination angle on the damage and damage evolution of the specimen and model were analyzed. The experimental results show that the damage of the specimens with prefabricated cracks increases greatly compared with the intact specimens, and the damage evolution of the specimens with prefabricated cracks varies with the different distribution of the cracks under uniaxial compression load, and the damage evolution of the specimens with prefabricated cracks varies with the different distribution of the cracks. The damage evolution of the specimen is closely related to its fracture mode. The damage-plasticity model with prefabricated single crack is numerically calculated by using the damage-plasticity model based on ABAQUS finite element program. The results show that tensile damage is always greater than compression damage, that is, the appearance of airfoil crack caused by tension can be used as a marker of crack initiation. With the increase of crack thickness, the crack tip compression damage and the crack tip tensile damage decrease, but with the increase of the crack length, the crack tip compression damage and the crack tip tensile damage gradually increase. The velocity of crack initiation angle increasing with crack dip angle is greater than that with crack thickness and crack length.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU45

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