Method for dynamically monitoring crack tip stress intensity factor

Abstract

The invention relates to a method for dynamically monitoring a crack tip stress intensity factor, which comprises the following steps of: selecting an organic mechanoluminescent material to prepare a solution; uniformly coating the surface of the metal sample with an organic mechanoluminescent material solution, and heating to form a film; calibrating fluorescence intensity by using a tensile sample coated with the mechanoluminescent material, and establishing a relation curve between the fluorescence intensity and stress; carrying out a tensile experiment by using the single-side notch sample coated with the mechanoluminescent material, and collecting fluorescence images of the crack tip under different loading forces; processing the fluorescence image, and quantitatively obtaining the boundary and intensity of a fluorescence area; solving a stress intensity factor and T stress by utilizing a relation curve of fluorescence intensity and stress on the boundary and according to a deviatoric stress criterion; and comparing the stress intensity factor limit Kc with the stress intensity factor limit Kc of the material, and carrying out safety evaluation on the in-service engineering structure with the defects. The method can be popularized to complex mechanical structures or loading conditions, and has important reference value for mechanical structure design and health detection.

Description

technical field [0001] The invention relates to a method for dynamically monitoring the stress intensity factor at the tip of a crack by using an organic luminescent material with a mechanosensitive response property. Background technique [0002] With the development of the global economy, large and complex components are widely used in aerospace, high-speed rail, and automobiles. In order to ensure the safety and durability of components, a wide range of health monitoring and safety assessments are required to protect personnel and equipment. safety is of great importance. There are often various defects or cracks in the actual structure in industrial applications, which will significantly reduce the actual strength of the structural material and endanger the normal use of the engineering structure. Therefore, it is of great significance to quickly and accurately analyze it and dynamically monitor the stress intensity factor of the crack tip for the evaluation of the safe...

AI Technical Summary

Problems solved by technology

However, the intensity distribution of organic mechanofluorescence on metal surfaces is discontinuous, and the boundary and intensity of fluorescence cannot be directly and accurately determined, which brings difficulties to the quantitative analysis of mechanical damage.

The use of organic electroluminescence materials to dynamically monitor the stress intensity factor of crack tip has not been reported yet

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