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 insta lled grid-based tactile pressure sensors at the ice-structure interface to measure the pressure generated during an interaction. Similar to the result s of earlier studies, the results of the present study with compliant struc tures show that there is ductile deformation of ice at low indentation spee ds and continuous brittle crushing at high indentation speeds. During a typ ical cycle of the dynamic ice-structure interaction at intermediate speeds, the ice-structure interaction results in variable rates of indentation int o the ice, and the tactile sensor data indicate that the ice deforms in a d uctile manner at the low indentation rate (the loading phase), and fails in continuous brittle crushing at the high indentation rate (the ejection pha se). Theoretical estimates of global force are given in terms of non-simult aneous local force per unit width during continuous brittle crushing. We fi nd the effective pressure measured during small-scale indentation tests to be close to those measured on full-scale structures, when the indentation r ate is high in both situations. (C) 2001 Elsevier Science Ltd. All rights r eserved.