Temperature-strain integrated measuring method in high-temperature tension test

Abstract

A temperature-strain integrated measuring method in high-temperature tension test comprises the following steps: 1) establishing a relation between gray scale and temperature; 2) in the calibration stage: (1) heating material to be detected, collecting temperature change data of points to be measured by a two-color thermometer, and collecting image data simultaneously by an industrial camera; (2) converting the image data into a grey-scale map in a computer and extracting the grey level of the tested points; (3) fitting a formula according to the gray level data and the temperature data; and (4) determining parameters A and B; and 3) in the measuring stage: (1) extracting initial coordinates and initial grayscale characteristics of two mark points in an initial grey-scale map; and (2) converting the grey-scale map into a temperature map according to the relation between gray scale and temperature and the parameters A and B obtained in the calibration stage, so that full-field temperature can be obtained in real time. Meanwhile, by utilizing the initial grayscale characteristics of the two mark points and through an initial scale distance L and a follow-up scale distance L', scale distance change delta L can be obtained, thereby obtaining axial strain delta L / L. Through the utilization of the two-color thermometer and the high-resolution industrial camera, both high-precision full-field high temperature measurement and high-precision strain measurement are realized.

Description

technical field [0001] The invention belongs to the technical field of temperature and strain measurement, in particular to a temperature-strain integrated measurement method for simultaneous measurement of the temperature field and axial strain of the entire region under ultra-high temperature. Background technique [0002] At present, temperature measuring instruments are mainly divided into two categories: contact type and non-contact type. Commonly used contact measuring instruments mainly include thermocouples, resistance thermometers and semiconductor thermistor thermometers, etc., which are characterized by simplicity, intuition and reliability. However, its temperature measurement range is generally below 2000°C, and the contact method is likely to affect the temperature of the measured object; and in actual operation, its dynamic characteristics are poor and the response time is long. The other is a non-contact temperature measuring instrument developed by the prin...

AI Technical Summary

Problems solved by technology

However, the strain gauge is sensitive to the temperature of the measured point, and temperature fluctuations and thermoelectric coupling effects will have a great impact on the results

Due to the limitation of the resistance strain gauge material, its service temperature cannot reach a higher temperature

The non-contact method developed in recent years is mainly the digital image correlation method, which can realize the measurement of the strain field at 1200 °C, and it is difficult to further apply it to the measurement at higher temperatures: on the one hand, the surface speckle preparation at high temperature has encountered challenges , on the other hand, it is impossible to measure

[0004] In addition, the existing temperature and strain measurement systems are independent systems. For the situation where temperature and strain need to be measured at the same time, there is no temperature-strain integrated measurement system.

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