共查询到18条相似文献，搜索用时 93 毫秒
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定量风险评估是风险评估发展的主要趋势。论文基于TOPS IS和神经网络响应面法,提出一种定量风险分析方法,并运用此方法对导管架海上安装过程进行深入分析,以及时查找并消除各方面的事故隐患。首先找出潜在的风险事件及相关风险因素,然后对风险事件的模糊概率和损失程度后果进行量化,最后依据风险评价结果对需要控制的风险事件给出控制措施。实例表明,该方法是一种实用而有效的定量风险评估方法。 相似文献
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回顾和总结了当前防波堤项目的决策模型,介绍了效用理论的起源、发展和理论基础,提出了效用理论结合防波堤风险量化方法的新型风险决策模型.以某直立式防波堤的优化设计为例,将防波堤滑移失效概率、防波堤尺度、生命周期内的风险损失和预期收益、决策者风险态度等量化指标纳入决策系统,比较了费用最小化、费用-收益权衡和效用三种决策模型,探讨了优化设计重现期的确定.结果表明,决策者的风险态度将极大地影响防波堤方案的选择,而费用-收益模型实质上是效用模型的一种特殊情况,这凸显了效用模型的包容性和合理性. 相似文献
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为科学评估河口型水源地供水安全风险,基于水源地特点,在建立相应供水安全风险评估指标体系的基础上,采用层次分析法确定指标权重,结合选取灰色关联度法和BP神经网络法对某河口型水源地分别开展供水安全风险分类评估。以某次咸潮入侵事件数据为例,经采用两种方法评估后对比表明:灰色关联度法能较好地解决评价指标难以准确量化和统计的问题,具有定性与定量相结合评价精度较高的优点,更适合于河口型水源地供水安全风险分类评估。该水源地风险分类评价等级由高到低依次排序:水量风险(较高)→应急风险(较低)→工程风险(较低)→水质风险(低),其结果与实际相符。 相似文献
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针对FPSO软刚臂单点系泊系统出现过的系泊腿失效及背向工况风险事件,以渤海某16万吨级FPSO为例,采用数值模拟的方法,计算FPSO及单点系统在百年一遇海况下的载荷效应,通过统计学方法拟合效应的概率分布,完成定量风险分析。对于系泊腿旋转失效后的风险,使用故障假设(what-if)方法,依据失效后果判断其风险权重。计算结果表明,系泊腿结构在正常情况下受拉失效的概率很小;系泊腿纵摆失效后导致的结果比横摆失效更为严重,风险权重更大。背向工况下,船艏与YOKE的间距要明显小于顺向工况,在设计时增大二者间距可有效减小碰撞风险。 相似文献
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为克服典型情景模拟法的缺陷,综合考虑船舶溢油发生的随机性、海洋水动力和风场的不确定性以及环境资源的敏感性,提出基于随机情景模拟的船舶溢油危害后果定量评价方法。通过随机情景模拟和网格化统计得到敏感区的溢油污染概率和最快到达时间,结合环境敏感指数和溢油量等参数计算综合溢油危害指数,并将其作为溢油危害后果定量评价指标。结果表明:台湾海峡北部水域不同季节发生船舶溢油的危害后果大小依次为夏季(27.8)秋季(25.5)春季(21.1)冬季(16.2),夏季溢油事故对牛山岛保护区的污染概率和危害后果相对最大(P=60%,Ck=41.2),达到较高级别;其他季节东甲列岛保护区的溢油污染概率和危害指数均为最高。随机情景模拟能够弥补事故情景,为评价船舶溢油危害后果风险提供一种新方法。 相似文献
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从保护对象及其生境的保护与管理角度出发,构建了基于概率和损失度的海洋保护区生态风险的综合评价方法。以滨州贝壳堤岛与湿地自然保护区为例,通过历史数据、遥感资料分析,筛选风暴潮、海岸侵蚀、海水污染、围填海、海冰、溢油等6种风险源,利用层次分析法确定权重并计算综合风险概率;根据贝壳堤、滩涂、养殖池塘等9种生境的自然生态、社会经济属性及生境的脆弱度,计算各生境的综合损失度;在地理信息系统(GIS)技术支持下,完成保护区生态风险的综合评价,对不同级别的风险区提出管理对策。对发展我国海洋保护区生态风险评价方法以及保护区范围科学选划调整等管理工作都有参考价值。 相似文献
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《海洋湖沼通报》2017,(2)
副溶血弧菌是一种重要食源性致病菌,牡蛎是其主要携带者之一。为了量化评估牡蛎养殖过程中副溶血弧菌感染的风险,采用德菲尔法、层次分析法和多指标综合体系评价法,将专家经验知识和现代数学方法结合,构建了由评估指标体系、风险因素权重、评分标准、综合评价函数等组成的牡蛎养殖过程中副溶血弧菌风险评估模型。其中,评估指标体系包括水质、养殖管理、健康状况等3个准则层和水温、盐度、pH、氨氮、亚硝酸盐、溶解氧、养殖模式、养殖密度、场址选择、日常管理、细菌感染、病毒感染、寄生虫感染等13个指标层风险因素;3个准则层风险因素权重值集合为W={0.5278,0.3325,0.1396},指标层风险因素中水温(0.2270)、盐度(0.1368)和养殖密度(0.1409)等权重值较高,为影响副溶血弧菌感染的主要风险因子;分别建立了定性和定量评估指标的评分标准。以广东阳江某牡蛎养殖场为例,运用多指标综合体系评价法对该模型进行验证,得出该牡蛎养殖场春季、夏季、秋季和冬季副溶血弧菌感染发生风险概率为分别0.2281、0.5833、0.2723和0.1347,评估结果与实际调查结果相符,说明该模型可用于牡蛎养殖中副溶血弧菌感染风险估算。 相似文献
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基于模糊影响图(FPID)和失效模式与效果分析(FMEA)建立了一种海洋结构风险分析方法。鉴于风险分析中某些事件发生概率和关系概率两个重要参数确定时需借助专家主观判断,本文将模糊概率的概念引入海洋结构影响图评估方法中。该方法成功地应用到海洋平台人员伤害分析中。虽然这里仅给出了该方法在海洋平台风险评估中的应用,但其具有更广泛应用价值。 相似文献
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Economy and ice-resistance are two factors that must be considered in the design of offshore oil platforms in the Bohai Gulf. This paper focuses on the optimal design of ice-resistant offshore jacket platforms in the Bohai Gulf in consideration of fatigue life of tubular joints, with the minimum initial weight and satisfying dynamic properties. An efficient fatigue analysis procedure based on spectral analysis is proposed, in which a hybrid finite element model is adopted to simulate the jacket platform and the tubular joints, and the pseudo-excitation method is used to calculate the power spectral density of the hot spot stress. Finally, a practical jacket platform with an ice-breaking cone in the Bohai Gulf is optimized, and the results demonstrate that the fatigue life of tubular joints could be improved and the weight of jackets decreased simultaneously. 相似文献
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海洋平台结构风险评估 总被引：5，自引：1，他引：5
作为结构系统可靠性方法与结构损伤冗余设计的一个合理延伸与综合，结构风险评估与决策技术是近年来得到迅速发展的新方法。本文讨论了海洋平台结构风险评估的理论框架，涉及了结构风险评估的几个基本方面，为进一步进行详细研究确立了一条主线。本文还对导管架式平台的结构风险评估进行了简要讨论。 相似文献
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以一6.7 MW风机为研究对象，提出了一种适用于30~50 m水深的海上风电倒Y形导管架筒型基础结构型式，采用三维精细有限元模型对结构的受力特性展开研究，包括结构的自振特性以及在随机风浪流荷载作用下的动力响应。研究结果表明，倒Y形导管架筒型基础采用“三腿变六腿”导管架的结构型式，能够更加有效的将上部荷载传递至下部筒型基础，具有较好的受力特性和传力体系；整机结构的前两阶自振频率均在风机允许运行的频率范围内；在50年一遇极端随机风浪流荷载作用下，整机结构的位移响应和应力响应，均可满足结构安全使用要求。 相似文献
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Tarek Elsayed 《Applied Ocean Research》2009,31(3):179-185
A multiple attribute risk assessment approach using a fuzzy inference system is developed in this work. The approach is based on the use of fuzzy sets, a rule base and a fuzzy inference engine. Traditional input probabilities and consequences used in risk assessment are represented by fuzzy sets to take into account uncertainties associated with the assignment of their values. The output risk values can be presented as crisp values or fuzzy sets with associated degree of membership. The fuzzy inference system FIS is used as an alternative approach to qualitative risk matrix techniques currently used in many industries and by ship classification societies. Two approaches for fuzzy inference are adopted. These include the Mamdani approach in which output risk values are fuzzy sets and the Sugeno method of fuzzy inference, in which output risk values are constant or linear.The use of a fuzzy set approach is particularly suited for handling multiple attribute risk problems with imprecise data. It improves upon existing qualitative methods and allows the ranking of risk alternatives based on a unified fuzzy risk index measure. Results show that while the Mamdani method is intuitive and well suited to human input, the Sugeno method is computationally more efficient and guarantees continuity of the final risk output surface. Results also show that computed risk values using a fuzzy risk index measure are consistent with those obtained using a qualitative risk matrix approach. The proposed methodology is also applicable to other ship operating modes such as transit in open sea and/or entering/leaving port. A case study for a liquefied natural gas LNG ship loading/offloading at the terminal is presented to demonstrate the developed approach capability. 相似文献
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研究了大型导管架平台卧式建造时出现单边约束圆管的风致涡激振动问题。将建造过程中单边约束的导管架圆管简化成悬臂梁模型,采用van der Pol尾流振子模型模拟圆管受到的流体力,建立了圆管风致涡激振动动力学方程。使用伽辽金方法对建立的运动方程进行求解,数值分析了圆管在特定约化风速下的涡激振动特性。在圆管上附加非线性能量阱(NES)作为被动减振装置对圆管进行减振,并采用粒子群优化算法对NES的非线性刚度和阻尼参数进行了优化。结果表明,在约化速度为4.8时,得到的NES优化的非线性刚度和阻尼参数组合可以有效减小悬臂梁自由端风致涡激振动位移。本研究说明采用NES和粒子群优化算法可以有效减小圆管的风致涡激振动,为导管架安全建造提供一定的参考。 相似文献
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Parametric study on offshore jacket launching 总被引：1，自引：0，他引：1
Platform structures are commonly utilized for various purposes including offshore drilling, processing and support of offshore operations. Jacket type structures are attractive in relatively shallow water regions. A jacket is a supporting structure for deck facilities stabilized by leg piles through the seabed. The size of a jacket is dependent on deck size, pile dimensions and environmental loads. In a jacket design, operational and environmental loads are very important and must be investigated intensively to secure the stability of structures during their operation life, and installation phase as well. To confirm the stability, several analyses including in-place, fatigue, dynamic, load-out, transportation, lifting, and launching are performed. As the jacket weight and dimensions become large, a launching technique is applied to install the jacket. The launching analysis needs to consider quite a number of parameters including environmental conditions, launch barge specification, ballast, trim angle, local member integrity, etc. Due to the complexity of the operation, there is not a straightforward guideline or procedure for analysis. In this paper, a general procedure for analysis with various conditions and launching criteria are discussed and investigated. The effects of parameters are closely examined by numerical modeling. 相似文献