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中文核心期刊

海冰与自升式海洋平台相互作用GPU离散元模拟

GPU-BASED DISCRETE ELEMENT MODELLING OF INTERACTION BETWEEN SEA ICE AND JACK-UP PLATFORM STRUCTURE

  • 摘要: 在海冰与自升式海洋平台结构的相互作用过程中,冰载荷是影响平台结构振动响应和疲劳寿命的重要因素. 采用具有粘接-破碎效应的离散元模型,可对海冰与自升式海洋平台结构作用中的海冰破碎特征及相应冰载荷进行数值分析. 针对自升式海洋平台的多桩腿结构特性及其冰载荷离散元分析的大规模计算需求,建立了基于GPU 的并行算法并开发了相应的计算程序. 为实现离散元分析的高效计算,采用网格排序方法创建单元邻居列表,以快速确定海冰单元间及其与平台结构间的接触模式和作用力. 此外,还发展了球体单元与圆柱形结构在不同接触形式下的计算模型. 为检验该离散元模型的有效性,对渤海锥体海洋平台结构的作用过程进行了计算,并与现场实测冰力数据进行了对比验证. 在此基础上对多桩腿自升式平台结构的冰载荷进行了离散元分析,获得了海冰的破坏特性,确定了不同桩腿上的冰力时程. 该模型可进一步应用于不同类型海洋结构的冰载荷分析,为冰区海洋平台的结构设计和现役平台结构的疲劳分析提供参考依据.

     

    Abstract: During the interaction between sea ice and jack-up platform, the ice load is the key factor affecting vibration response and fatigue life of the structure. In this study, a discrete element method (DEM) with bonding-breaking function is developed to simulate the breakage characteristics of ice cover and the relative ice load on platform structure. According to the demand in the large scale DEM simulation between the sea ice and the jack-up platform structure with multi-legs, a parallel algorithm with high efficiency is established based on GPU (Graphical Processing Units) technique. In this algorithm, the element neighbor lists are generated with the sorting approach of cell index. The contact modes and contact forces between element-element and element-structure are determined. Meanwhile, the global ice load on jack-up structure can also be obtained. Moreover, the contact models between spherical element and cylindrical structure are also developed to determine the interaction between ice cover and jack-up structure. To validate this GPU-based DEM, the interaction between sea ice and conical jacket offshore structure is simulated and compared well with the field data in the Bohai Sea. Moreover, the ice loads on jack-up structure with multi-legs are simulated. The breakage characteristics of sea ice during the dynamic interaction and the ice loads on each structure legs are obtained. This GPU-based DEM can be applied to determine the ice loads on different offshore structures for ice-resisted structure design and ice-induced structure fatigue analysis.

     

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