Extension of reflection-mode digital gradient sensing method for visualizing and quantifying transient deformations and damage in solids

• The reflection-mode Digital Gradient Sensing (r-DGS) is extended to experimental mechanics and NDE.
• Role of different experimental parameters of r-DGS are studied.
• r-DGS is demonstrated for stress wave induced deformation studies in solids.
• Feasibility of r-DGS for detecting impact induced damage is demonstrated.

The reflection-mode Digital Gradient Sensing (r-DGS) method is extended to visualize and quantify dynamic deformations in solids due to stress wave propagation and for damage/disbond detection in layered materials due to impact loading. The r-DGS technique employs digital image correlation principles to quantify two orthogonal surface slopes simultaneously in specularly reflective solids. Here, for the first time, r-DGS has been implemented in conjunction with ultrahigh-speed photography to quantitatively map surface slopes during stress wave propagation in a thin plate due to an impact event. The measured surface slopes have also been used to successfully evaluate instantaneous topographic information. The r-DGS method has been subsequently demonstrated to be an effective tool for detecting disbonds in layered structures subjected to impact loading. Baseline experiments in each category have been carried out to demonstrate the methodology.