海洋石油平台结构全寿命周期动态鲁棒性分析

为有效描述海洋平台服役周期内结构整体对于"突发局部损伤"的抵抗能力——鲁棒性,综合考虑了波浪载荷、腐蚀作用和结构材料的随机性,以及由于疲劳与腐蚀导致的平台结构承载能力退化,定量刻画了"突发事件"引发局部损伤的时间、类型和位置的不确定性,提出一种全寿命周期动态鲁棒性指标。在此基础上,建立了退化平台结构动态鲁棒性的评价方法和流程,采用MonteCarlo随机模拟方法,从系统动态失效概率的角度评价平台结构的鲁棒性。模拟示例结果表明:在服役后期疲劳和腐蚀退化对于结构鲁棒性的影响明显;且通过控制初始裂纹的尺寸改善平台的初始状态,可有效提高平台服役后期的鲁棒性。

Dynamic robustness analysis of the offshore platform in the whole life cycle

To effectively demonstrate the resistance capability of offshore platform structure to unexpected local damages in service period, i.e., robustness, this study takes full consideration of wave load, corrosive effect of structure material, and loading-capacity deterioration of the platform structure caused by fatigue and corrosion, quantifies the uncertain factors of unexpected local damage such as occurrence time, type and location, as well as proposes a dynamic robustness index for the whole life cycle of offshore platform. On this basis, the evaluation method and process of dynamic robustness has been built for the deteriorated platform structure; the robustness is evaluated using Monte-Carlo stochastic simulation method from the perspective of the system dynamic failure probability. The results show that the deterioration caused by fatigue and corrosion exerts a significant impact on the structure robustness; the initial condition of offshore platform can be improved by controlling the sizes of initial cracks, thus efficiently enhancing robustness in the late service period.