Dynamic-stress induced elastic weakening and healing in jammed granular materials.

Understanding healing processes in granular materials under dynamic loading is paramount for assessing risks in geological hazards. However, dynamic healing - the crucial process of stiffness recovery occurring concurrently with sustained vibration - remains largely uninvestigated, which significantly constrains accurate predictions of the dynamic performance of granular materials. Our experimental results show that following an initial weakening, sustained dynamic excitation drives significant dynamic healing without obvious sample volume change. This phenomenon, providing fundamental insight into granular mechanical properties under persistent dynamic stress, can be interpreted through the effective contact radius increasing under vibration. Consequently, accurate prediction of mechanical evolution of granular materials in dynamic geological and engineering environments necessitates a comprehensive understanding of the complex interplay between dynamic weakening and dynamic healing. All the data are from the author's experimental results.