准脆性材料黏聚阻裂的计算与实验

Calculation and Experiment on Cohesive Resistance Crack of Quasi-Brittle Materials

工程常用材料铸铁混凝土等,在裂缝前端区域有微观及宏观缺陷的变化及能量耗散,表现为准脆性损伤断裂特点。若把该阻止裂缝扩展与张开的损伤发展区简化成虚拟裂纹,将存在裂纹黏聚分布力与变形或张开位移;讨论了与此相关的黏聚裂纹力学模型及方程解答说明。相应于黏聚张开位移有微细观测图与实验测试数据,给出黏聚裂纹模型的解析计算方法,并将理论计算与实验测试数据进行了对比。以双K断裂准则和黏聚模型为基础,给出对含裂纹结构的承载力的预估计算。理论计算比较符合实验结果。

In engineering materials such as cast iron and concrete, there is a fracture process zone in the crack front and it exists micro and macro defect and energy dissipation, so its quasi-brittle fracture performance prevail. The damage development area is simplified into virtual crack, and crack cohesive stress distribution and opening displacement or deformation exist among it. In order to explore the constitutive relation of crack opening displacement and stress of cohesive crack in quasi brittle materials, cast iron and concrete were used to test their fracture process and micro view experiment. By the analytical method of applied mathematics mechanics, the material deformation stress constitutive relations were obtained for the crack development zone. And, based on the mechanical mode/and double K fracture criterion, the estimate calculation of structure bearing capacity with crack was also given in the paper. The theoretical calculation and test results are basically identical.