Quantitative Evaluation of the Relationship between Strain and Color Change in Opal Photonic Crystal Films and Application into Complex Specimen Geometries

The color change of opal photonic crystal films (OPCFs) due to deformation was quantitatively evaluated using digital image correlation (DIC) analysis. OPCFs were pasted on specimens three different gauge geometries, and random patterns formed the opposite side each specimen for DIC To assess applicability OPCFs-based strain characterization analyzing steel structural components associated metallurgical analyses, smooth, width-gradient, holed prepared in this study. As increased smooth specimen, changed significantly. could be converted into values through Hue value Heterogeneous distributions also analyzed analysis at submillimeter or millimeter scale. When gradient is too high, example, near a stress concentration site such as hole, local peeling away from surface can occur. Consequently, quantitative characterization, we must take proper care when measuring upper limit “strain gradient” well strain, which would depend adhesion condition specimen.