Experimental Study of Dynamics During Crushing of Freshwater Truncated Conical Ice Specimens

Ice crushing dynamics in ice structure interactions can result in hazardous vibrations and potentially damaging loads on offshore structures. Ice cone crushing experiments were conducted in the lab to characterize loading and dynamics processes for compressive failure. The indentation rate, temperature and shape of the ice specimens were varied in control tests so that the sensitivity of the resultant dynamic ice load frequency and amplitude could be determined. The results indicate that all control variables had a marked effect on both the frequency and amplitude of load fluctuations. Indentation rates varying from 0.1 mm/s to 10 mm/s and ice taper angles from 13° to 30° had drastic effects. The effects of temperature also demonstrated variations in force, pressure and dynamic behavior. In addition to load measurements, video was used to observe failure mechanisms and in particular spalling and crushing. In the present paper observations are described, though a thorough quantitative assessment has been published elsewhere. Tactile pressure sensors were also used in the experiments, allowing for the correlation of loads and processes to pressure distributions. Finally, the forensic examination of crushed specimens also provided insights into the behavior of ice under various compressive failure scenarios. On the surfaces of intact specimens and revealed within through cross-polarized views of thin sections were signs of ice damage and recrystallization zones of varying extents. The effects of the variables on the dynamic processes and failure behaviors are discussed.