An optical measurement device and method for uniform strain based on double-mirror reflection

Abstract

The invention discloses a homogeneous strain optical measurement device based on double-mirror reflection.The device comprises a light source, a first reflecting mirror, a second reflecting mirror, a camera and a processor; the light source is used for generating incoherent light and irradiating a first measured surface and a second measured surface of a measured sample, the first measured surface and the second measured surface are parallel to each other and both parallel to the optical axis of the camera; the first reflecting mirror is used for enabling the first measured surface to be reflected to a lens of the camera to be imaged; the second reflecting mirror is used for enabling the second measured surface to be reflected to the lens of the camera to be imaged; the camera is used for simultaneously collecting images of the first measured surface and the second measured surface in a same image and transmitting the images to the processor for processing to obtain strain of the measured sample.The invention further discloses a measurement method of the homogeneous strain optical measurement device based on double-mirror reflection.According to the device and method, nondestructive measurement can be performed on the measured sample which is initially bent, and false strain caused by off-plane rigid body displacement is corrected.

Description

technical field [0001] The invention relates to the technical field of uniform strain measurement, in particular to an optical measurement device and method for uniform strain based on double-mirror reflection. Background technique [0002] For a long time, uniaxial loading test has been one of the most commonly used and reliable methods in testing the basic properties of materials. Uniaxial testing can be used to measure mechanical parameters such as tensile strain, elastic modulus, and Poisson's ratio of the tested sample. In uniaxial testing, traditionally, contact methods such as resistance strain gauges and extensometers are used to measure the strain of the tested sample. However, contact measurement hinders the deformation of the sample surface to a certain extent, and is easy to cause damage to the sample surface, which is unacceptable in more and more new material testing fields. In non-contact measurement methods like uniaxial tests, the application of laser inter...

AI Technical Summary

Problems solved by technology

However, contact measurement hinders the deformation of the sample surface to a certain extent, and is easy to cause damage to the sample surface, which is not acceptable in more and more new material testing fields

In non-contact measurement methods like uniaxial tests, the application of laser interferometry is limited due to the harsh isolation conditions and measurement environment. The commercialized video extensometer has the advantage of optical measurement, but its measurement results are extremely Susceptible to the interference of the out-of-plane displacement of the measured sample, which seriously deviates from the real data

Images