A Stress Measurement Method Based on Terahertz Time Domain Spectroscopy System

Abstract

The invention discloses a terahertz time-domain spectroscopy system-based stress measurement method. The method comprises the following steps: placing an experimental piece and loading equipment into a constructed terahertz spectroscopy system together; generating a terahertz pulse by utilizing a femtosecond laser, and receiving a signal by utilizing a terahertz detecting device; acquiring phase frequency curves under an unloaded working condition and a loaded working condition; performing subtraction on the two phase frequency curves to obtain a terahertz wave phase difference value caused by external stress; reversely deducing a stress component of an loaded experimental piece by utilizing the change of a terahertz wave phase; optimizing the stress component of the experimental piece through a target function, and acquiring a final stress result. A transparent material can be measured by the method, and a non-transparent material can also be measured by the method without manufacturing an experimental model. According to the method, an improved terahertz time-domain spectroscopy system is utilized; the internal stress information of a loaded piece is obtained by analyzing the phase change of a terahertz wave; a new experiment means is provided for detecting the internal stress of an object.

Description

technical field [0001] The invention relates to the field of stress measurement, in particular to a stress measurement method based on a terahertz time-domain spectroscopy system. Background technique [0002] The current method of measuring material stress is limited to the photoelastic method, which is a non-contact measurement method, which uses the optical fringe image of the model to display the size and distribution of the mechanical physical quantities in the structure under study. With this method, we can understand the overall picture of the internal stress or displacement distribution of the structure, especially the stress concentration area and the three-dimensional internal stress problem, which is intuitive and clear at a glance. However, this method has limitations, that is, an experimental model is required, and the material (for example: epoxy resin) is required to have a uniform texture and good transparency, which limits the detection range and the develop...

AI Technical Summary

Problems solved by technology

However, the traditional terahertz time-domain spectroscopy system does not meet the requirements of experimental stress measurement and cannot directly measure stress, so it needs to be improved and perfected according to the principle of experimental mechanics

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