加载方向对海冰脆性破坏时单轴压缩强度的影响-海洋预报

加载方向对海冰脆性破坏时单轴压缩强度的影响

单位：1. 营口市海洋环境预报站, 辽宁营口 115007;
2. 国家海洋环境预报中心, 北京 100081;
3. 辽宁省海洋预警监测中心, 辽宁沈阳 110001;
4. 大连理工大学工业装备结构分析国家重点实验室, 辽宁大连 116023

关键词：海冰脆性破坏加载方向单轴压缩强度现场试验

分类号：P731.15

出版年·卷·期（页码）：2019·36·第四期（52-59）

摘要：

对渤海的柱状海冰开展了系统的现场单轴压缩试验。在试验过程中，分别采用垂直于（水平加载）/平行于（竖直加载）冰晶的两种加载方向。同时，通过改变加载速率的方式研究了应变速率对压缩强度的影响。在测试结果中，结合试样的应变、应力以及裂纹特征分析了脆性破坏模式下海冰单轴压缩强度特征。试验结果表明：平行于冰晶方向的加载强度约为垂直于冰晶方向强度的3倍，并且两种加载方向的海冰单轴压缩强度均随加载速率的提高而降低。破坏模式的分析表明：脆性破坏主要由裂纹的发展所主导。随着加载速率的提高，海冰的破坏过程由单次破碎向多次破碎转变从而弱化了压缩强度。由于裂纹更容易在晶界处发展，不同加载方向下的裂纹特征以及最终的破坏模式有所区别。水平加载下的破坏模式以剪切形式为主，而竖直加载时主要发生柱状冰晶的屈曲破坏。屈曲破坏更容易发生在冰晶内部而表现出较高的压缩强度，因此竖直压缩强度更高。

For design of offshore structures and vessels in ice infested waters, the uniaxial compression strength is a key parameter. In this paper, uniaxial compression tests were systemically carried out on the sea ice in the northeast region of the Bohai Sea. Based on growth history, the ice was believed to own a columnar structure. Two loading directions were applied:parallel to grain columns (horizontal) and perpendicular to grain columns (vertical). Meanwhile, various loading speeds were performed to study the influence of strain rates. The ice strength of brittle failure is analyzed based on the stress, strain and cracks. The results show that the vertical strength is approximately three times of horizontal strength, and in both loading directions the strength is decreased with increasing loading speed. The analysis of failure modes shows that the brittle failure is dominated by crack development. With increasing strain rate, the ice failure process changes from single fracture to multiple fracture. Since the crack tends to develop along the grain boundary, the loading direction leads to different final failure modes. The sample failed in shear faulting under horizontal loading, while in buckling under vertical loading. The buckling may cause internal grain fracture, which results in higher compressive strength for vertical compression.

参考文献：

[1] Timco G W, Weeks W F. A review of the engineering properties of sea ice[J]. Cold Regions Science and Technology, 2010, 60(2):107-129.
[2] 刘煜, 吴辉碇. 第1讲渤、黄海的海冰[J]. 海洋预报, 2017, 34(3):94-101.
[3] 胡展铭, 陈伟斌, 唐茂宁, 等. 辽东湾东岸海冰抗压强度特征分析[J]. 海洋预报, 2009, 26(4):11-18
[4] 李志军, 王永学. 渤海海冰工程设计特征参数[J]. 海洋工程, 2000, 18(1):61-64, 69.
[5] Yen Y C. Review of thermal properties of snow, ice and sea ice[R]. Hanover NH:Cold Regions Research and Engineering Laboratory, 1981.
[6] Su B, Riska K, Moan T. Numerical study of ice-induced loads on ship hulls[J]. Marine Structures, 2011, 24(2):132-152.
[7] Moslet P O. Field testing of uniaxial compression strength of columnar sea ice[J]. Cold Regions Science and Technology, 2007, 48(1):1-14.
[8] 孟广琳, 张明远, 李志军, 等. 渤海平整冰单轴抗压强度的研究[J]. 冰川冻土, 1987, 9(4):329-338.
[9] Schulson E M, Nickolayev O Y. Failure of columnar saline ice under biaxial compression:failure envelopes and the brittle-to-ductile transition[J]. Journal of Geophysical Research:Solid Earth, 1995, 100(B11):22383-22400.
[10] Ince S T, Kumar A, Paik J K. A new constitutive equation on ice materials[J]. Ships and Offshore Structures, 2017, 12(5):610-623.
[11] Li Z J, Zhang L M, Lu P, et al. Experimental study on the effect of porosity on the uniaxial compressive strength of sea ice in Bohai Sea[J]. Science China Technological Sciences, 2011, 54(9):2429-2436.
[12] 陈晓东, 王安良, 季顺迎. 海冰在单轴压缩下的韧-脆转化机理及破坏模式[J]. 中国科学:物理学力学天文学, 2018, 48(12):124601.
[13] 李志军, 孟广琳, 隋吉学. 辽东湾海冰单轴压缩长期强度的初步分析[J]. 海洋学报, 1991, 13(4):571-575.
[14] 贾斌, 李加雷, 庞宝君, 等. 平面应力I型准静态扩展裂纹尖端场的弹粘塑性分析[J]. 机械工程学报, 2011, 47(8):99-103.
[15] 王安良, 许宁, 季顺迎. 渤海沿岸海冰单轴压缩强度的基本特性分析[J]. 海洋工程, 2014, 32(4):82-88.
[16] Kim H, Keune J N. Compressive strength of ice at impact strain rates[J]. Journal of Materials Science, 2007, 42(8):2802-2806.
[17] Qi C F, Lian J J, Ouyang Q A, et al. Dynamic compressive strength and failure of natural lake ice under moderate strain rates at near melting point temperature[J]. Latin American Journal of Solids and Structures, 2017, 14(9):1669-1694.
[18] Lu W J, Lubbad R, Løset S. Out-of-plane failure of an ice floe:radial-crack-initiation-controlled fracture[J]. Cold Regions Science and Technology, 2015, 119:183-203.
[19] 季顺迎, 王安良, 刘宏亮. 渤海海冰侧限压缩强度的影响因素分析[J]. 海洋通报, 2014, 33(4):371-376.
[20] 季顺迎, 刘宏亮, 许宁, 等. 渤海海冰断裂韧度试验[J]. 水科学进展, 2013, 24(3):386-391.
[21] Renshaw C E, Schulson E M. Universal behaviour in compressive failure of brittle materials[J]. Nature, 2001, 412(6850):897-900.
[22] Fortt A L, Schulson E M. Velocity-dependent friction on Coulombic shear faults in ice[J]. Acta Materialia, 2009, 57(15):4382-4390.
[23] Schulson E M. Low-speed friction and brittle compressive failure of ice:fundamental processes in ice mechanics[J]. International Materials Reviews, 2015, 60(8):451-478.
[24] Lian J J, Ouyang Q A, Zhao X, et al. Uniaxial compressive strength and fracture mode of lake ice at moderate strain rates based on a digital speckle correlation method for deformation measurement[J]. Applied Sciences, 2017, 7(5):495.

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