Experimental Results on the Tensile Strength of Atmospheric Ice

Abstract

The tensile strength of atmospheric ice samples (glaze and rime) obtained in an open type wind tunnel has been measured. Ice was grown from supercooled water droplets impinging on a rotating aluminium cylinder. In a first series of tests, the liquid water content of air was set at 0,8 g/m3 and the tensile strength of atmospheric ice was measured as a function of temperature ranging from −3 to −20°C, wind velocity during accretion ranging from 10 to 23 m/s and nominal strain rate ranging from 8, 70 × 10-7 to 1, 88 × 10-3 s-1. In a second series of tests, the liquid, water content of air was set at 1, 2 g/m3 and the wind velocity was maintained at 23 m/s. The tensile strength was measured as a function of temperature ranging from −3 to −20°C and larger nominal strain rate ranging from 7,25 × 10-8 to 7, 25 × 10−3 s−1. Maximum strengths, measured at −14°C, are found to be 5, 0 MPa at 1, 2 g/m3 liquid water content and 3, 1 MPa at 0, 8 g/m3 liquid water content. For the lowest temperatures used (−14 and −20°C), the atmospheric ice tensile strength increases with strain rate in the ductile range, i.e. strain rates lower than about 10−6 s−1. In these cases, the strength is found to be maximum for strain rate corresponding to the ductile-brittle transition and decreasing for higher strain rates. For the highest temperatures used (−3 and −8°C), the tensile strength of ice is found to be nearly constant as a function of strain rate.

A high throughput tensile ice adhesion measurement system

“…The tensile ice adhesion of PP and PE were independent of temperature within the range tested (Fig. 13a), similar to prior studies of tensile ice adhesion on other materials [13,14].…”

“…Cut and drill the aluminum sheets ( 9), (13), and ( 26) with respect to the dimensions depicted in Fig. 3.…”

“…There is no standard or high throughput system readily available, and few studies have utilized devices and methods that measure the adhesion of ice by applying a tensile force [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26]. Among them, Yan et al [27] used a universal mechanical testing machine to measure the tensile adhesion of ice by placing the entire measurement device into a freezing room in order to produce the ice.…”

Tensile strength of glacial ice deduced from observations of the 2015 eastern Skaftá cauldron collapse, Vatnajökull ice cap, Iceland

“…Here, we refer to ice strength as a bulk property equaling the maximum stress intact ice can sustain before fractures appear at macroscale, and we focus specifically on the tensile stress regime. Although there are some constraints on the tensile strength of glacier ice from laboratory experiments (Currier and Schulson, 1982; Lee and Schulson, 1988; Xian and others, 1989; Druez and others, 1989) and field observations (Vaughan, 1993), the ranges derived from the different methods barely overlap. Further, models disagree about what part of the observed range is relevant to glacier modeling and even what style of deformation – viscous, elastic or a combination – determines the stresses associated with fracture (e.g.…”

“…A major challenge in constraining the strength of glacier ice is that estimates derived from laboratory experiments do not agree with the limited estimates from in situ observations. Laboratory estimates range from 0.7 to 3.1 MPa (review by Petrovic, 2003) for laboratory and lake ice; Druez and others (1989) found tensile strength as high as 5 MPa for laboratory-grown glaze ice. In situ observations of glaciers, meanwhile, suggest a tensile strength ranging from 0.09 to 0.32 MPa for glacier ice (Vaughan, 1993).…”