Dynamic crack tip stress field measuring method and device

Abstract

An embodiment of the invention disclose a dynamic crack tip stress field measuring method and a dynamic crack tip stress field measuring device, which relate to the technical field of stress field experimental research. The dynamic crack tip stress field measuring method comprises the steps of: using digital image acquisition equipment to acquire images before and after the surface of a test specimen deforms after being loaded; searching for a sub-region in which a second mass point locates in the image after deformation, wherein the sub-region in which the second mass point locates is matchedwith a sub-region in which a first mass point locates in the image before deformation; calculating displacement information of the first mass point before and after deformation; and calculating a stress field according to the displacement information of the first mass point. The dynamic crack tip stress field measuring method and the dynamic crack tip stress field measuring device are applicableto crack detection and mechanical laboratory.

Description

technical field [0001] The invention relates to the technical field of stress field experimental research, in particular to a method and device for measuring a dynamic crack tip stress field. Background technique [0002] Scholars at home and abroad have proposed many experimental methods and theories in the research field of stress field distribution and expansion mechanism around dynamic cracks. Classical experimental mechanics methods include strain electrometry and photometry. The basic principle of the strain electrical measurement method is to measure the linear strain on the surface of the component with the resistance strain gauge, and then determine the stress state of the surface of the component according to the strain-stress relationship. This method belongs to the contact measurement method. Specifically, the resistance strain gauge is pasted on the surface of the measured component. When the component is deformed, the resistance value of the resistance strain ...

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Problems solved by technology

However, this method is complicated to operate, and the sticking of strain gauges is affected by manual proficiency, which will affect the accuracy of measurement results

[0003] Existing mechanical methods of optical measurement, such as holographic interferometry, photoelasticity, and moiré interferometry, can visually display the deformation information on the surface of the test object. However, this type of measurement method needs to be carried out in a darkroom environment during the experiment. Moreover, vibration isolation is required, and the accuracy of its measurement results is easily affected by the external environment

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