Article ID Journal Published Year Pages File Type
743213 Optics and Lasers in Engineering 2015 9 Pages PDF
Abstract

•Speckle patterns at the micrometer level used up to 1400 °C were developed for DIC.•Chemical and physical change of patterns at high temperature affect DIC accuracy.•MIG alone is not enough to evaluate the pattern properties for a good DIC.

Speckle patterns to be used for digital image correlation (DIC) at the micrometer level up to 1400 °C were fabricated by several methods. The quality of the patterns before and after heating was evaluated in terms of the mean intensity gradient (MIG) and the speckle size distribution. The displacement accuracy in simulative translation of images showed that the MIG alone was not enough to evaluate the pattern properties; a large MIG, an even speckle size distribution, and a wide speckle size range pattern were required for a good DIC. The reaction between the patterning material and substrate, the cracking of speckles, and the plastic flow of patterning material may cause changes in the pattern morphology at high temperature. Two patterning methods, spraying a mixture of ceramics powder and binder by a fine-nozzle air brush and abrading a polished surface, yielded a small pattern with high MIG values and even size distributions that was stable at 1400 °C. The potential of the fabricated patterns was shown by measuring the coefficient of thermal expansion of polycrystalline Al2O3 from 800 °C to 1400 °C.

Related Topics
Physical Sciences and Engineering Engineering Electrical and Electronic Engineering
Authors
, , ,