加载方向对海冰脆性破坏时单轴压缩强度的影响  

Influence of loading direction on uniaxial compressive strength of sea ice with brittle failure pattern

作　　者：宋洪芳 隋俊鹏[2] 刘煜[2] 李子牛 王兆宇 陈海军 陈晓东[4] SONG Hong-fang;SUI Jun-peng;LIU Yu;LI Zi-niu;WANG Zhao-yu;CHEN Hai-jun;CHEN Xiao-dong(Marine Environmental Forecasting Station of Yingkou,Yingkou 115007 China;National Marine Environmental Forecasting Center,Beijing 100081 China;Marine Monitoring and Early Warning Center of Liaoning Province,Shenyang 110001 China;Dalian University of Technology.State Key Laboratory of Structure Analysis of Industrial Equipment,Dalian 116023 China)

机构地区：[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

出　　处：《海洋预报》2019年第4期52-59,共8页Marine Forecasts

基　　金：国家重点项目研究发展计划项目（2017YFF0206900）;国家自然科学基金（41676189）

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.

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[天文地球—海洋科学]