Determination Of Quasi Brittle Material Fracture And Strength Parameters Of Boundary Effect Theory And Model Research

Fracture mechanics experiment is an important means of fracture parameters,and at present in ordinary laboratory equipment and experimental conditions,the determination of the crack opening displacement parameters,there is still a larger error and the requirement of test conditions for determination of the peak load is relatively low.Model in this paper based on the boundary effect,the peak load method is adopted to determine the fracture toughness of the material and tensile strength.This article through to concrete,mortar and rock materials such as non-standard three-point bending beam fracture test.BEM based on boundary effect model,proposed by mortar under quasi brittle fracture and rock specimen peak load at the same time to determine the material fracture toughness and tensile strength of theory and method.In this paper,at the same time will be the largest particle size of aggregate is introduced into the fault model of expressions,according to the parameters of the portfolio beta,to calculate the peak state corresponding to the amount of crack extension structure,by adjusting the parameters of the beta value to realize the of material parameters,fracture toughness and tensile strength of accurate prediction.Different seam height ratio,at the same time,through the same size and same seam geometric similarity ratio of different size of mortar,the rock of this kind of quasi brittle material test results,verify the rationality and applicability of the proposed method.