【摘要】 将混凝土视为由骨料、水泥砂浆及二者间的粘结带所构成的三相复合材料,利用蒙特卡罗方法生成混凝土随机骨料模型。在此基础上,采用双折线损伤演化模型描述混凝土细观各相单元的损伤退化。利用非线性有限元方法对湿筛、三级配、四级配混凝土试件的单轴受压破坏过程进行了数值分析,从而对试件的抗压强度进行了尺寸效应分析。研究结果表明,数值模拟所得的结果与试验结果表现出较好的一致性,混凝土的断裂主要发生在骨料与砂浆的粘结面上,裂纹沿平行于最大压应力的方向扩展。更多还原

【Abstract】 The concrete is considered as a three-phase composite composed of matrix,aggregate and interface between them,and its mesoscale structure is represented with random aggregate model by using Monte-Carlo method.Then,the bilinear damage evolution model is adopted to describe the meso-element’s damage degradation,and the failure mechanism of wet screened,three-graded,four-graded concrete specimens under uniaxial compression is simulated with nonlinear finite element method.Furthermore,size effect on the strength is analyzed in the paper.The results show that the numerical solutions are fitted with experiment results, and the fracture of concrete is generally generated along the bond between aggregate and matrix,Cracks are extended in a direction parallel to the maximum compression stress.更多还原