Dynamic loading optical measurement-electrical measurement hybrid experiment system and method

Abstract

The invention discloses a dynamic loading optical measurement-electrical measurement hybrid experiment system and method. The system comprises a light source device (1), filter (2), a beam expander (3), convex lens 1 (4), a polarizing film 1 (5), a quarter-wave plate 1 (6), a test piece loading table (7), a spectroscope (9), a quarter-wave plate 2 (10), a polarizing film 2 (11), a convex lens 2 (12), a convex lens 3 (13), a high-speed camera 1 (14), a high-speed camera 2 (15), a super-dynamic strain gauge (21), a data collector (22), bridge boxes (16-20), a trigger strain gauge (25), a straingauge and a signal line. According to the system, a transmission type photoelastic method, a transmission-type defocusing method, a digital speckle method and an electric measurement method are effectively combined together, the advantages of an optical measurement method and software calculation are integrated, and the strain, the dynamic stress intensity factor, the crack initiation toughness change, the initiation, expansion and crack arrest speed, the dynamic energy release rate and the like of the whole crack movement process under the dynamic condition can be accurately obtained simultaneously. With comparative analysis of experimental results measured by the four methods at the same time, the crack propagation law of sample transient damage under various dynamic loading conditions can be studied more accurately, comprehensively, systematically and scientifically.

Description

technical field [0001] The invention relates to a dynamic fracture mechanics experimental method in the professional field of experimental mechanics, in particular to the research on the whole process of crack initiation, expansion and mutual interference under dynamic loading. Background technique [0002] In engineering projects such as rail transit engineering, tunnel engineering, and mining engineering, the stability of engineering materials has a very important impact on the safety of the engineering. The dynamic failure of engineering materials is a variable and complex process under the action of multiple conditions. Study the failure mechanism of materials under dynamic conditions, analyze the stress-strain field of crack initiation and expansion, crack initiation toughness, expansion toughness and other mechanical parameters, and summarize the dynamic fracture mechanical properties of materials under dynamic loading, which can provide future engineering Practice pr...

AI Technical Summary

Problems solved by technology

At present, scholars at home and abroad have achieved certain results in the research on the dynamic fracture characteristics of various materials, but the dynamic fracture mechanism of materials such as rocks before damage to complete destruction has not been fully understood.

On the one hand, it is limited by the own characteristics of rock or rock-like materials, such as opacity; on the other hand, it is one-sided to use a certain experimental method alone to study the fracture characteristics of materials, and it is impossible to obtain sufficient experimental data, and the dynamic failure process has Instantaneous, difficult to capture and even harder to analyze

Both the transmission photoelastic method and the transmission caustic method can visually observe the crack growth and the stress-strain field at the crack tip. The disadvantage is that the research material needs to have good light transmission.

The electrical measurement method and the digital speckle method do not have high requirements on whether the specimen can transmit light, and the strain field displacement field can be quickly obtained through computer calculation, but the crack tip position cannot be directly observed, which has a large error

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