Characterization of mechanical behaviors for the dynamic shear rupture by photoelastic fringes in time series

Abstract

Visualization and quantitative characterization of mechanical behaviors in shear rupture propagation along fault interfaces play a critical role in elucidating mechanism of the dynamic rupture. Recent advances in laboratory-scale fault modeling have significantly advanced the characterization of dynamic shear rupture processes through synergistic integration of optical measurement techniques, including digital image correlation, photoelasticity, and real contact zone monitoring. While time-series analyses of these methods have yielded important insights, the temporal evolution of photoelastic fringe patterns with multiple orders-a crucial diagnostic feature to characterize dynamic shear rupture behaviors − remains underexplored in dynamic rupture studies. This study firstly presents time-series photoelastic fringes with multiple orders induced by impact loads to investigate dynamic shear rupture mechanisms. Fault models were 3D-printed, and dynamic shear experiments were conducted under varying boundary conditions. High-speed imaging captured fringe evolution near fault surfaces, from which time-series fringes were extracted. Based on variations observed in these time-series fringes, rupture tip propagation characteristics, rupture velocity transitions, spatiotemporal evolution of stress fields, local fault slip distributions, and the nucleation and rupture of fault were analyzed. By offering direct insight, the technique confirms the potential of time-series photoelastic fringes for elucidating the intrinsic mechanisms of dynamic shear fracture.