Method for testing dynamic fracture expansion toughness of brittle material

Abstract

The invention relates to a material performance detection method, and discloses a method for testing the dynamic fracture expansion toughness of a brittle material.The method comprises: A) preparing a sample (1) with a straight cutting groove (11), and spraying a dot matrix reference system on the observation surface of the sample; B) performing a three-point bending loading experiment on the sample, and measuring the displacement of each scatter point in the reference system along the horizontal and vertical directions by using a digital image measuring device to obtain a cloud chart of the displacement of the scatter points along the horizontal and vertical directions; C) determining geometric centers of the two fractured bodies before the sample is fractured by using a digital image measuring device and a computer through a geometric method, and determining displacements of the geometric centers along the horizontal direction and the vertical direction by combining the displacement cloud atlas; and D) calculating the unit area dissipated energy in the fracture process of the sample, and combining the performance parameters of the sample and the loading parameters of the experiment to obtain the dynamic fracture extension toughness. The method for measuring the dynamic fracture expansion toughness of the brittle material is high in measurement precision.

Description

technical field [0001] The invention relates to a method for testing material properties, in particular to a method for testing dynamic fracture extension toughness of brittle materials. Background technique [0002] With the depletion of shallow resources and the decreasing surface space, projects such as resource mining and underground space development gradually enter the deep ground. The construction and operation of deep ground projects are closely related to rock and concrete as the main body and supporting materials. [0003] These materials are prone to brittle fracture failure under high-speed impact loads, and their instability failure process is controlled by fracture parameters, especially the dynamic fracture propagation toughness. Dynamic fracture propagation toughness is an important parameter reflecting the high-speed crack growth, which is closely related to the fracture translational velocity and fracture rotational velocity. [0004] At present, the metho...

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Problems solved by technology

[0004] At present, the method commonly used to test the fracture propagation toughness of rock-like brittle materials is mainly the high-speed camera method, but it is difficult to accurately measure the centroid distance before and after the sample is destroyed, which makes it difficult to calculate the fracture translational velocity of the sample, which is largely Relying on data processing experience, this makes the measurement results of fracture propagation toughness have great errors, which cannot serve as a good reference for understanding the dynamic fracture failure mechanism of rocks

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