Tensile properties of impact ices

A special test apparatus was developed to measure the tensile strength of impact ices perpendicular to the direction of growth. The apparatus consists of a split tube carefully machined to minimize the effect of the joint on impact ice strength. The tube is supported in the wind tunnel by two carefully aligned bearings. During accretion the tube is turned slowly in the icing cloud to form a uniform coating of ice on the split tube specimen. The two halves of the split tube are secured firmly by a longitudinal bolt to prevent relative motion between the two halves during ice accretion and handling. Tensile test strength results for a variety of icing conditions were obtained. Both glaze and rime ice conditions were investigated. In general, the tensile strength of impact ice was significantly less than refrigerator ice. Based on the limited data taken, the median strength of rime ice was less than glaze ice. However, the mean values were similar.