Visualizing dual-surface stress distribution of transparent soft materials by combining fluorescence imaging-based dual-surface DIC and hyperelastic constitutive modeling

Abstract

Transparent soft materials are critical components in flexible electronics. The inherent material heterogeneity and complex microstructures within these devices often lead to highly non-uniform stress distributions, causing local stress concentrations that precipitate deformation and failure. However, it has so far been challenging to experimentally visualize the full-field stress distribution in transparent soft materials. To address this challenge, a practical and effective stress reconstruction method that combines fluorescence imaging-based dual-surface digital image correlation (DIC) and hyperelastic constitutive modeling is presented. By fully utilizing deformation data from both surfaces together with through-thickness deformation to determine the principal stretches required for hyperelastic stress calculation, this method enables simultaneous dual-surface stress reconstruction. To show the applicability of the proposed method, an adhesive specimen composed of transparent soft materials is prepared and subjected to tensile testing. A comparison of reconstructed dual-surface stress field results with simulated reference values demonstrates the efficacy of the proposed method. The stress reconstruction method combining fluorescence imaging-based dual-surface DIC and hyperelastic constitutive modeling provides a novel approach for evaluating and optimizing the mechanical reliability of transparent soft materials.