Dynamic breakage of double glass spheres chain subjected to impacting loading

Abstract

Strain energy releasing due to local failure plays an important role in the dynamic breakage of the brittle medium. A series of experiments are conducted based on the Split Hopkinson pressure bar (SHPB) device. Two contact modes, i.e. the rigid contact between two spheres and the elastic contact between the sphere and the impact/support bar, are introduced by using the double sphere chain sample. Two methods, e.g. the Infrared temperature measurement (ITMS) method and the Digital image correlation (DIC) method, are utilized to trace the fracture sequence of the chain samples under impact velocity 5.0–13.0 m/s. The effects of strain energy releasing to the force-displacement curves, the temperature rising process, and the broken products of the chain samples are demonstrated in detail. Releasing of strain energy causes a delayed recompression process, and the delayed time decreases with increasing of impact velocity, which was caused by the formation and releasing of local strain in elastic contact mode. The approaches to evaluate the effects of strain energy releasing are then proposed to analyze the force-displacement curves and the temperature rising process. The elevated temperature is estimated to be a linear relationship to ε˙2/3. It is of great significance for the profound understanding of the failure mechanism of sphere aggregates.