中文摘要：

针对海洋平台服役周期内突发致损事件“小概率,高风险”的非比例后果特性,综合考虑常规疲劳退化与突发致损的耦合作用,定量分析了局部突发致损的直接后果及结构倒塌失效的潜在间接后果。从风险分析理论的角度,提出海洋平台结构风险鲁棒性指标,并基于Monte-Carlo随机模拟,建立了风险鲁棒性的评价方法及评价流程。通过相应算例,分析海洋平台结构全寿命周期内风险鲁棒性指标的动态特征及影响因素,并讨论了检修行为对结构鲁棒性控制的作用。模拟示例结果表明,在平台服役后期,初始损伤及疲劳退化对风险鲁棒性指标的影响愈加显著,完好平台结构的风险鲁棒性指标明显高于含初始损伤平台,至服役的第30年,两种平台的风险鲁棒性指标分别由1下降至0.913和0.67。同时,4种不同突发事件单独作用下的模拟结果表明,对风险鲁棒性影响最为显著的突发事件是爆炸,其后依次是船舶碰撞、突发火灾和重物坠落。突发事件发生后采取快修措施可有效提高其风险鲁棒性指标,且为保证平台结构维持合理的风险鲁棒性水平而采取“非完好维修”是更为经济可行的选择。

英文摘要：

This paper is to engage itself in conducting a quantitative analysis for the direct consequence of the local damage and the indirect consequence of the overall structure collapse of the offshore platforms. We would like to study the coupling effects of the conventional degradation to be caused by the fatigue and sudden local damage resulted from the accidental events. And,then,based on the risk analysis theory,we would like to present a new risk robustness indexical system for analyzing such events. Furthermore,taking the advantage of Monte-Carlo stochastic simulation,we have developed an assessment method and process for judging the risk robustness. And,finally,we have made a detailed analysis of the dynamic characteristics and the influential factors of the robustness index for the entire life-long cycle of the offshore platform structure through the numerical simulated samples,and,then,have given a discussion of the effects of the sustenance performance on the robust control. The simulation results show that it would be more and more urgent and significant to study the effects of the initial damage and fatigue degradation on the risk robustness in the late service stage of the platform,which will inevitably bring about a greater risk robustness index of the intact platform than that of the platform with initial damage of crack. To our knowledge,the risk of the two types of platforms tend to decrease from 1 to 0. 913 and 0. 67 by its 30 service years,respectively. Thus,it may suggest that it is absolutely necessary to do the corresponding timely inspection and maintenance activities for the platform structure,so as to get rid of any serious hazards in the late service years. Also,the risk robustness indexes of the platform under the above said four different kind of accidental events are calculated respectively. And,the results of our study indicate that exposure to the burst explosion can be expected to be the greatest adverse factor for the platform safety,which should also be followed by ship collisions,like