爆炸荷载作用下海洋平台结构的动力响应分析

Dynamic Response Analysis of Offshore Platform under Blast

采用理想化的压力—时间曲线模拟爆炸冲击荷载,压力—时间曲线为简化的三角形荷载形式。考虑应变率效应对钢材的影响,应用LS-DYNA有限元分析软件,对导管架海洋平台在爆炸冲击荷载作用下的动力响应进行数值模拟和分析,得到了不同峰值爆炸荷载作用下,海洋平台结构上层甲板、中层甲板和立面结构重要节点的动力响应时程曲线。结果表明:上层甲板和中层甲板节点竖向位移的绝对值随着爆炸荷载峰值压力的增大而增大,当爆炸荷载峰值压力为20～70kPa时,节点区域内均处于弹性状态,当爆炸荷载峰值压力为80kPa时,节点区域内进入了塑性状态。立面平台节点的水平位移随着爆炸荷载峰值压力的增大而增大,当爆炸荷载峰值压力为20～80kPa时,节点区域内进入塑性状态。

Idealized pressure-time curve is adopted to simulate explosion load.The pressure-time curve represents simplified triangular load.Considering the influence of strain rate effect on steel,numerical simulation and analysis of dynamic response of jacket offshore platform under blast are performed by LS-DYNA software.Dynamic time-history response curves of key nodes in the upper deck,middle deck and vertical structure under different blast load are obtained.Results show that the absolute values of vertical displacements of the upper deck and middle deck nodes increase with increase of explosion load peak pressure.When the explosion load peak pressure ranges from 20 to 70 kPa,the material near these nodes is in the elastic stage.When explosion load peak pressure reaches 80kpa,the material enters the plastic stage.Horizontal displacements of elevation platform nodes increase with increase of explosion load peak pressure.Material near monitoring points in elevation platform enters plastic stage when explosion load peak pressure varies from 20 to 80 kPa.