Measurement method of crack tip stress intensity factor of cylindrical shell with axial crack

A technology of stress intensity factor and cylindrical shell, which is applied in the field of fracture mechanics and optical testing, can solve problems that hinder the expansion of fracture mechanics engineering applications, and achieve reliable test results, simple data processing, and accurate experimental results.

Inactive Publication Date: 2016-05-04
TSINGHUA UNIV
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Problems solved by technology

Although a lot of research has been done on the application of focal line technology, most of them are limited to plane problems, and the lack of research on the crack tip stress intensity factor of curved thin shells such as cylindrical shells with cracks hinders the application of this technology to a large extent. The Development of Fracture Mechanics and Its Application in Engineering

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  • Measurement method of crack tip stress intensity factor of cylindrical shell with axial crack
  • Measurement method of crack tip stress intensity factor of cylindrical shell with axial crack
  • Measurement method of crack tip stress intensity factor of cylindrical shell with axial crack

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Embodiment Construction

[0021] The specific structure, working principle and working process of the present invention will be further described below in conjunction with the accompanying drawings, but the protection scope of the present invention should not be limited by this.

[0022] figure 1 It is a schematic diagram of the structure principle of the projected caustics optical testing system provided by the present invention, the system includes a laser light source 1, a beam expander 2, a first imaging lens 3, a second imaging lens 4, a three-point bending loading device 5, and a CCD camera 7 and a computer 8; the laser light emitted by the laser light source 1 is acted on by the beam expander 2, refracted by the first imaging lens 3 and becomes parallel light, and passes through the cylinder containing the axial crack 9 bearing the three-point bending load The shell specimen 6 is converged by the second imaging lens 4, and the image is received by the CCD camera 7. The CCD camera 7 is connected ...

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Abstract

A measurement method of a crack tip stress intensity factor of a cylindrical shell with axial crack belongs to the technical fields of fracture mechanics, and optical testing. The method uses caustics optical testing technique; a CCD camera is employed to shoot a shadow spot photography of the cylindrical shell with axial crack after loading; characteristic size of the shadow spot is measured; and through the relationship between the stress intensity factor and the characteristic size of the shadow spot, the crack tip stress intensity factor of cylindrical shell with axial crack under certain load is obtained. The present invention uses non-contact measurement; and compared to optical technologies such as photoelastic method and digital speckle correlation method, the method has simple data processing and reliable test results; compared with a traditional electric measurement method, the method eliminates complex process of plastering strain gauges each time, and is more simple and convenient. For the measurement of the crack tip stress intensity factor of the cylindrical shell with axial crack, the invention provides a caustics measurement method, introduces the radius of curvature and thickness of the cylindrical shell into the relationship of stress intensity factor and characteristic size of the shadow spot, so as to reach more accurate results.

Description

technical field [0001] The invention relates to a caustic line optical test technique for measuring the stress intensity factor of a cylindrical shell containing axial cracks, belonging to the technical fields of fracture mechanics and optical test. Background technique [0002] Caustics optical testing technology is an important means to study the fracture mechanics behavior of materials and structures, and it can simply and accurately measure the crack tip stress intensity factor. Although a lot of research has been done on the application of caustic technology, most of them are limited to plane problems, and the lack of research on the crack tip stress intensity factor of curved thin shells such as cylindrical shells with cracks hinders the application of this technology to a large extent. The development of fracture mechanics and its application in engineering. It is urgent to propose a caustics test measurement method for the crack tip stress intensity factor of cylind...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N21/88
CPCG01N21/8806G01N21/8851G01N2021/8874
Inventor 姚学锋刘伟马寅佶原亚南
Owner TSINGHUA UNIV
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