冰在低温下的单轴压缩力学行为和破坏机制

利用带有低温装置的Instron5848材料实验机和分离式Hopkinson压杆装置(SHPB),在-10℃、-20℃和-30℃温度下,对多晶冰进行了应变率为10-4~102 s-1范围内的单轴压缩力学性能实验,分析了实验结果的可靠性和有效性.研究发现:冰的压缩强度具有明显的温度和应变率敏感性,随应变率的增大、温度的降低而提高;压缩强度与应变率对数呈线性关系,应变率的升高会增强降温对压缩强度的强化效应.在研究的应变率和温度范围内,冰主要有径向膨胀、纵向劈裂和整体破碎三种破坏模式,内应力释放速率和氢键强度的变化是导致多晶冰破坏模式改变的主要原因.

Mechanical Behavior and Failure Mechanism of Ice at Cryogenic Temperatures under Uniaxial Compression

By using an Instron 5848 material testing machine and a split Hopkinson pressure bar (SHPB) with cooling chambers, a series of uniaxial compression experiments were carried out to explore the mechanical behaviors and failure mechanism of polycrystalline ice at temperatures of -10/ -20 /-30℃ and at strain rates in the range of 10-4S-1 to 102S-1. The reliability and effectiveness of the experimental results were analyzed. The experimental results show as follows. The compressive strength of ice is sensitive to temperature and strain rate obviously. It also increases with the increase of strain rate and the decrease of temperature. There is a linear relationship between the compressive strength and the logarithm of strain rate. The increase of strain rate enhances the strengthening effect of the compression strength due to the decrease of temperature. Within the studied strain rate and temperature scope, the ice mainly has three types of failure modes, namely expansion, longitudinal splitting and holistic crushing. The different ice failure modes and the increase of compressive strength are caused by the energy of the crack tip can not be released in time, the increase of the hydrogen bond strength and the friction resistance of the crack slipping in the ice.