Crushing failure during ice-structure interaction

Small-scale indentation tests were conducted with compliant structures and freshwater ice sheets. Besides measuring forces and displacements, we installed grid-based tactile pressure sensors at the ice-structure interface to measure the pressure generated during an interaction. Similar to the results of earlier studies, the results of the present study with compliant structures show that there is ductile deformation of ice at low indentation speeds and continuous brittle crushing at high indentation speeds. During a typical cycle of the dynamic ice-structure interaction at intermediate speeds, the ice-structure interaction results in variable rates of indentation into the ice, and the tactile sensor data indicate that the ice deforms in a ductile manner at the low indentation rate (the loading phase), and fails in continuous brittle crushing at the high indentation rate (the ejection phase). Theoretical estimates of global force are given in terms of non-simultaneous local force per unit width during continuous brittle crushing. We find the effective pressure measured during small-scale indentation tests to be close to those measured on full-scale structures, when the indentation rate is high in both situations. (C) 2001 Elsevier Science Ltd. All rights reserved.