| An investigation on the behavior of an interfacial crack in an ice-substrate system was performed. The analysis, which included both laboratory experiments and numerical analysis, used interfacial fracture mechanics theory and looked at ice cast onto acrylic, aluminum, concrete, and steel substrates. Asymmetric tapered double cantilever beam and asymmetric double cantilever beam specimens were used. These specimens were shown to be capable of repeatedly producing sustained interfacial fracture. Results indicated that for the acrylic, aluminum, epoxy, and steel, a relationship exists between the crack tip eccentricity {dollar}(epsilon),{dollar} the augmented mode mixity angle {dollar}(psi),{dollar} and the interfacial energy release rate {dollar}({lcub}cal G{rcub}sb{lcub}c{rcub}).{dollar} Results also indicate that the interfacial crack for the specimens with a concrete substrate produced energy release rate data comparable to cohesive fracture. This appears to be due to the surface roughness of the specimens with a concrete substrate. Thin-section analysis of the ice sheets grown in the specimens indicated that the non-metallic substrates produced ice that appeared to be S1 ice and that the metallic substrates produced ice that did not appear to be one of the standard classifications. Photomicrographs established that the fracture events at the interface were true interfacial fracture. The use of M-dimensional cubic spline surfaces to describe multi-dimensional failure surfaces and specimen calibrations is proposed and implemented. A technique to artificially initiate cracks for interfacial fracture specimens is presented. |
