In-Ice Calibration Tests for an Elongated, Uniaxial Brass Ice Stress Sensor

An elongated, uniaxial brass ice stress sensor has been developed by the University of Alaska and used in several field experiments. Laboratory calibration tests have been conducted, in a 60 × 29.5 × 8.5 in. (1524 × 750 × 216 mm) ice block into which the sensor was frozen, to determine the sensor’s response characteristics. Test results indicate that the sensor acts as a stress concentrator with a stress concentration factor of 2.4 and transverse sensitivity of −1.3 at stresses below 30 lbf/in² (207 kPa). At stresses greater than 30 lbf/in² (207 kPa) the stress concentration factor increased and the sensor exhibited a time delay response to load. Differences of 22 percent were measured between the measured sensor stress immediately after a constant ice load was applied and the asymptotic stress limit. Interpretation of measured sensor stresses can be considered reliable at ambient ice stress levels below 30 lbf/in² (207 kPa).