Research on synchronous measurement technique of temperature and deformation fields based on fluorescent speckles

Abstract

The mechanical-thermal coupled load affects the stability and reliability of Printed Circuit Boards (PCBs) during their service life. The synchronous acquisition of temperature-strain data can provide supports for PCB evaluation and structural design optimization. In traditional methods, the resolution of the visible light image is higher than the infrared, which results in the low accuracy of multi-source image fusion and the difficulty in high-precision multi-field synchronous measurement. Therefore, a multi-field coupling measurement method is proposed based on the fluorescent speckles, which simultaneously measure the temperature and deformation fields. On one hand, the speckles are prepared by the fluorescent paint, whose fluorescence intensity ratio can change regularly at different temperatures for the dual-waveband temperature measurement. Then the grayscale ratio-temperature curve of the fluorescent speckles is calibrated to measure the surface temperature field based on the colorimetric method. On the other hand, the speckle images before and after the deformation are used to measure the surface strain field, which is analyzed by the digital image correlation based on integral graph acceleration. Experimental results prove that the proposed method can obtain the temperature and deformation information based on speckle grayscale ratio and correlation, and also can realize the high-precision synchronous measurement of the surface temperature and strain.