Real-Time Monitoring of Strain Processes With Large-Range and High-Spatial Resolution Using the Method of Weak Reflection FBG Measurement Based on OFDR

Abstract

The real-time monitoring of strain processes that can simultaneously realize a wide range and high spatial resolution has always been a huge challenge and cannot be satisfied by traditional electrical and non-contact measurement methods. In this article, the OFDR collocated with weak reflection FBG sensor (WRFBGs) was proposed to actively carry out multiple experiments on the non-standard reinforcement samples with complex strain processes in order to overcome this challenge. According to the result analysis, the complex strain variation law of the surface of the sample and the large span strain of adjacent locations during the whole process of tensile can be obtained by this method. The yield point (YP) can be accurately captured and positioned with mm-level horizontal precision. At the same time, real-time monitoring can be realized for the step process when the strain of the point increases to more than 25000με instantly. The method can also realize the strain detection capability with a response speed of 38 Hz and a 1.28 mm high spatial resolution with monitoring the real-time high-density and large strain distribution.

Strain Measurement Technology and Precision Calibration Experiment Based on Flexible Sensing Fiber

“…R is the initial resistance of the metal wire, as seen in Equation (1), the resistance of the resistance wire is subjected to force, the rate of change of its resistance is proportional to the strain produced by the resistance wire, which is the working principle of the strain gage [ 16 ]. K 0 is called the sensitivity coefficient of the resistance wire, and its value is a constant in the proportionality limit of the stretching of the resistance wire.…”