Material dynamic fracture tenacity measuring device based on Hopkinson bar

Abstract

The invention discloses a material dynamic fracture tenacity measuring device based on a Hopkinson bar. The material dynamic fracture tenacity measuring device based on the Hopkinson bar comprises a buffer device, a bearing device, a Hopkinson bar experimental device, a shooting device and a sample with a notch. The bearing device comprises a bottom plate, a vertical plate and a lifting displacement table. Two long-strip-shaped semi-circular supports used for supporting the sample are arranged on the vertical plate, and two vertical limiting devices are arranged on the side face, adjacent to the sample, of the vertical plate. A large-diameter through hole is formed in the middle of the vertical plate, and the notch of the sample is located in the circle center of the large-diameter throughhole. The Hopkinson bar experimental device comprises an incident bar, a striking bar and a semi-circular impact head. One end of the semi-circular impact head makes contact with the sample, and theother end of the semi-circular impact head is fixedly connected with the incident bar. The shooting device comprises a CCD camera and a light source arranged on the side face of the sample. A traditional three-point bending experimental method and the dynamic load are combined, fracture tenacity of a material under the dynamic load can be measured, and dynamic loading on the material can be achieved.

Description

technical field [0001] The invention belongs to the field of dynamic loading, and in particular relates to a material dynamic fracture toughness measuring device based on a Hopkinson rod. Background technique [0002] Fracture toughness is established on the basis of fracture mechanics to represent the toughness of materials against crack propagation and fracture. Usually, the fracture toughness of materials needs to be evaluated in both material failure analysis and damage tolerance design of structural parts. The dynamic fracture toughness of materials represents the anti-fracture ability of materials under dynamic loads. In the past, people mainly focused on the fracture toughness under static loads. Nowadays, there are more and more types of materials, and their application fields are also various. Some extreme In addition to static loads, materials in the environment will also be subjected to dynamic impacts during service, and dynamic loading is also a research hotspo...

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Problems solved by technology

However, due to the limitation of loading conditions, the test results are very helpful for evaluating structural members subjected to static loads, but it is not convincing to use this method for members subject to dynamic loads

In addition to three-point bending, people also use Charpy oscillometric impact test to measure the dynamic fracture toughness of materials, but this method is difficult to meet the conditions of plane strain due to the limitation of loading conditions. In addition, its load stability is poor and the strain rate is not stable. Stable, can not achieve high strain rate, can not simulate the real service environment of the material under dynamic load

[0004] The measurement of dynamic fracture toughness is difficult. The first is the limitation of loading methods. Traditional loading methods are mostly static loading with low strain rate, which cannot simulate the real service conditions of materials. To achieve dynamic loading, Hopkinson rods, air guns, etc. are required. method

Secondly, there is no relatively complete experimental device design on the experimental device that can combine dynamic loading and fracture toughness measurement

In addition to the limitations of experimental techniques, the complexity of inertial effects and stress wave propagation laws in dynamic fracture theory also brings difficulties to the measurement

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