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Experimental investigation of rate dependency of freeze bond strength
Cold Regions Science and Technology ( IF 4.1 ) Pub Date : 2020-10-01 , DOI: 10.1016/j.coldregions.2020.103120
Marjan Taghi Boroojerdi , Eleanor Bailey , Rocky Taylor

Abstract The effects of deformation rate on the shear strength of freeze bonds have been investigated through a series of Asymmetric Four-Point Bending (AFPB) experiments. Two submersion times of 30 min and 24 h have been considered, while the deformation rate has been varied from 0.01 to 100 mm/s. Ice specimens with an initial temperature of −18 °C have been subjected to a constant confinement of 25 kPa during formation and shearing of the freeze bonds. Failure of the bonds proved to be highly dependent on deformation rate, where more strain was observed prior to failure of the bond for slower deformation rates. The shear strength of the bond for both submersion times showed a general decreasing trend with increased deformation rate, which is of significant importance in characterizing the properties of ice ridge/rubble strength. Previous ice rubble strength experiments, as well as ice ridge keel gouging tests, have reported the same failure rate-dependency, highlighting the role of freeze bond failure on rate effects. Compressive strength measurements of solid ice presented in the literature have been observed to follow similar trends within the range of strain rates used in present study, where the failure mode appears to transition from ductile to brittle with increasing deformation rate. While more work is needed to understand the mechanisms associated with the rate dependency of freeze bond, this general observation suggests the rate dependency of ice ridges/rubble may indeed be related to the behavior of ice as a material, rather than being associated primarily with factors such as inertial and pore pressure effects, which have been previously proposed as the principal controlling mechanism.

中文翻译:

冷冻结合强度速率相关性的实验研究

摘要 通过一系列不对称四点弯曲 (AFPB) 实验,研究了变形速率对冷冻结合剪切强度的影响。已经考虑了 30 分钟和 24 小时的两个浸没时间,而变形速率从 0.01 到 100 毫米/秒不等。初始温度为 -18 °C 的冰样本在冻结键的形成和剪切过程中受到 25 kPa 的恒定限制。事实证明,结合的失效高度依赖于变形速率,在较慢的变形速率下,在结合失效之前观察到更大的应变。两种浸没时间的粘结剪切强度随着变形率的增加呈现普遍下降的趋势,这对于表征冰脊/碎石强度的特性具有重要意义。以前的冰碎石强度实验以及冰脊龙骨凿孔测试报告了相同的故障率依赖性,突出了冻结粘合破坏对速率效应的作用。已经观察到文献中提出的固体冰的抗压强度测量在本研究中使用的应变率范围内遵循类似的趋势,其中破坏模式似乎随着变形率的增加从韧性转变为脆性。虽然需要更多的工作来了解与冻结键的速率依赖性相关的机制,但这一普遍观察表明冰脊/碎石的速率依赖性可能确实与冰作为一种材料的行为有关,而不是主要与因素有关例如惯性和孔隙压力效应,
更新日期:2020-10-01
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