Method for testing brittle material dynamic-shear fracture toughness and implementation device thereof

Abstract

The invention discloses a method for testing brittle material dynamic-shear fracture toughness and an implementation device thereof. The method comprises the following steps of installing a cylindrical sample with annular precracks on a Hopkins pressure lever dynamic experiment device, applying a dynamic shear force for two ends of the cylindrical sample with the annular precracks arranged between an incident bar and a transmission bar by impacting the incident bar by an impact pellet, and calculating dynamic-shear fracture toughness KIIC of the brittle material and a corresponding loading rate by a strain value, incident bar and transmission bar cross sectional areas, pressure lever elasticity modulus and sample confining pressure value according to a formula provided by the invention. The method can acquire dynamic-shear fracture toughness of a quasi-brittle material and fills in gap of the research field.

Description

technical field [0001] The invention belongs to the field of performance testing of brittle materials, and in particular relates to a method for testing the dynamic shear fracture toughness of brittle materials by using a cylindrical sample designed with prefabricated cracks and an implementing device thereof. technical background [0002] The shear fracture toughness of brittle materials such as rock and concrete is a very important mechanical property of brittle materials. According to the documents retrieved by the inventor, the current measurement of the shear fracture toughness of brittle materials such as rocks and concrete is mostly performed on a material testing machine under static or quasi-static conditions. Tensile shear samples, etc. At the same time, there is an important problem in the above-mentioned shear fracture test, that is, the geometric configuration of the sample and the corresponding experimental loading conditions are difficult to avoid the additio...

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Problems solved by technology

At the same time, there is an important problem in the above-mentioned shear fracture test, that is, the geometric configuration of the sample and the corresponding experimental loading conditions are difficult to avoid the additional tensile stress component at the crack tip in the test. Shear fracture, the result is that the crack deviates from the original crack surface and expands, and the tensile stress has a great influence on the crack initiation

For the dynamic shear fracture toughness of brittle materials under high loading rate, due to the inertia effect caused by the stress wave and the stress singularity at the crack tip superimposed, due to the limitation of the current testing methods and methods, there has been no mature and feasible measurement method

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