Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : October 07, 2017 - October 09, 2017
Using a high-speed digital video camera system and a three-dimensional finite difference technique, we have been experimentally and numerically studying the physical characteristics of ice spheres that collide against a fixed elastic plate made of ice or polycarbonate. So far, we have demonstrated the dependence of the collective inelastic behavior of ice on the relative impact velocity and indicated the existence of two specific fracture patterns, “top” and “orange segments,” which may be found in ice spheres subjected to impact loading. By comparing the experimental observations with the numerically generated dynamic wave fields, we have also suggested that for the generation of “top”-type fracture pattern, surface waves of relatively short lengths play a crucial part while wider stressed areas expanding along the central axis of the sphere due to a longer contact time may produce the “orange segments”-type pattern. In this contribution, we further conduct dynamic laboratory experiments and observe fracture development in ice spheres under impact loading and try to confirm the presence of the two specific fracture patterns even without the pre-existence of material inhomogeneities (e.g. air bubbles) in the spheres. Since ice is one of the most familiar brittle solid materials in our environments, the obtained results may assist in understanding the generation mechanisms of a wide range of physical phenomena such as fracture of icebergs and avalanches.
