Dynamics behavior of porous tin under strong shockwave impact

Abstract

The dynamic fracture and fragmentation of solid materials subjected to shocks have been widely studied for several decades. Motivations for investigating shock-induced damage behavior are both practical and scientific. In many cases, the loading conditions are two or more continuous shockwaves, causing complex dynamic behavior. Understanding the complex dynamics of metal materials under multiple strong shockwave loadings is important for inertial confinement fusion and impact protection. Under multiple shockwave loadings, the shockwaves not only interact with the material, but also cause interactions among the particles in the porous structure produced by the first impact. These complex dynamics might be revealed by studying the impact response of metals with a clear three-dimensional pore distribution. In this study, experiments were performed on three kinds of porous tin with typical dimensions (millimeters, sub-millimeters, and micrometers) and a clear initial structure. The dynamic behaviors of the porous tins under a 10 GPa-order shockwave loading were characterized by X-ray images, high-speed photography, and photon Doppler velocimetry. The porous tin was not completely compacted after the shockwave, and many particles were ejected at velocities far exceeding the theoretical free-surface velocity. The post-shockwave material density and status of the high-speed ejection were closely related to the initial structure of the porous tin. The distribution characteristics of the material after the shockwave, and the generation mechanism of the high-speed jets, were determined in numerical simulations. After the shock loading, the surface spray was ejected at high speed and the particles inside the porous stucture collided with each other, also at high speed. The particle collisions in the porous structure contributed significantly to the high-speed ejections and the distribution of material density. This study is significant for understanding the dynamic responses of metal materials under multiple shockwave loadings.