FRACTURE TOUGHNESS OF S2 COLUMNAR FRESHWATER ICE: CRACK LENGTH AND SPECIMEN SIZE EFFECTS - PART II

Abstract

Wedge loaded compact tension (WLCT) specimens were tested to investigate the influence of both crack length and specimen size versus grain size on the fracture toughness of S2 columnar freshwater ice. For one grain size and one specific crack orientation, the crack length was varied as a function of the grain size, ranging over a major portion of the length of the specimen. The crack length effects on the critical energy release rate were studied in this way for three specimen sizes. Two parallel research efforts have already been completed using S2 ice but different loading configurations (Bentley et al 1988; Dempsey et al 1989). These previous studies and the present study allow preliminary observations to be made concerning the influence of specimen size and the comparative merits of the energy approach. The overall objective is to obtain a criterion for the minimum dimension in terms of grain size in order for small scale yielding conditions to apply.