腐蚀成本及控制策略研究

材料腐蚀对国民经济的发展造成严重的影响,因此腐蚀问题引起广泛关注.本文回顾了国内外在历史上几次主要的腐蚀调查工作,对国际通用的典型腐蚀成本调查统计方法进行了详细解读,并对重大咨询项目"我国腐蚀状况及控制战略研究"的主要工作做了重点陈述.腐蚀与防护是安全问题,是经济问题,是国计民生问题,是生态文明问题,更是国家文明发展程...     

玻璃钢渔船船体骨架结构形式的研究

通过对玻璃钢渔船的五种船体骨架结构形式的弯曲试验,测得其力学性能。并且运用加权因素法对试验结果进行优化。研究结果表明按断面形状,梯形优于矩形;按断面结构,木质芯材优于泡沫芯材,泡沫芯材优于空心结构。     

基于拓扑优化方法的船体支柱布局优化设计

船体支柱的布局影响到船舶功能性舱室的布置及相应的结构设计,而目前支柱布局多依赖母型船或者工程师设计经验,缺少基于数学优化的技术支撑。变密度的拓扑优化方法可将属于离散变量优化的支柱布局问题转化为连续变量优化问题。通过悬臂梁—支柱结构的算例,验证了该方法用于解决支柱布局优化问题的可行性。针对某型VLCC的支柱—大跨度甲板结构的支柱布局优化问题,根据布置限制条件设定了支柱优化设计域,选择了两种不同的优化目标函数进行支柱的布局优化设计,最后对优化结果进行了对比分析。结果表明,本方法具有较好的可行性,无需过多设计经验即可优化得到结构性能较好的支柱布局方案,可为此类的支柱布局优化设计提供技术支撑。     

渤南油气田海底管道内检测结果分析及评价

运用腐蚀分析的方法, 对渤南油气田海底管道的内检测结果进行了清出物分析、腐蚀规律分析及维修因子分析, 得出了管道的腐蚀规律和安全状况, 并提出了本条海管的运维建议。海底管道内检测结果腐蚀分析方法的应用, 是国内首次将这一办法系统地应用于海底管道内检测结果分析, 对于今后海底管道内检测的结果分析具有开创和借鉴意义。     

海水环境粉煤灰混凝土结构耐久性现场检测与评估分析

对服役12年的华南某跨海大桥典型构件开展碳化性能、氯离子扩散性能等指标的耐久性检测,评估了海水环境下掺粉煤灰的高性能混凝土长期耐久性。研究表明:随高程的增加混凝土碳化深度逐渐增大,其中大气区浪溅区水位变动区,碳化作用对粉煤灰混凝土结构耐久性的影响较小;粉煤灰可显著提升实体结构混凝土抗氯离子侵蚀性能,粉煤灰高性能混凝土的氯离子扩散系数不大于0.40×10-12m2/s,比普通混凝土氯离子扩散系数降低了约6倍;利用规范计算了引桥承台混凝土中氯离子含量计算值,其计算值与实测值吻合较好,可用于实体工程混凝土结构的耐久性评估,评估结果显示采用粉煤灰高性能的桥梁典型构件满足100年设计使用寿命的要求。     

基于海洋功能区的海域使用结构优化模型初探

探讨了海域使用结构形成机制,海域使用结构是受海洋资源结构约束,受消费结构引导,通过海洋产业落实到海域空间:分析了海域使用结构现状和变化趋势,结果显示渔业用海呈下降趋势,工业用海呈上升趋势;并以各类海洋功能区为基础,构建了海域使用结构优化模型,为海域使用结构调整提供定量化技术依据.     

海洋平台结构超声相控阵检测成像技术的发展及应用

介绍了超声相控阵检测成像技术的基本原理及其在海洋平台结构检测中的最新进展。超声相控阵技术采用区域划分法将焊缝分成垂直方向的若干区,由扫查器携带超声相控阵探头运动,对其分区进行电子扫查,检测结果以图像形式显示。探讨了超声相控阵技术用于海洋平台结构管节点焊缝检测时存在的一些问题,提出解决方法,指出其在海洋平台结构、压力容器、航空航天等工业无损检测领域将具有应用前景。     

影响海洋平台检测质量因素的模糊综合评判分析

本文通过对海洋平台结构实际检测工作的调查分析，着重研究了检测人员的失误对检测质量影响的主要因素，并运用模糊数学的基本理论，对包括人因素，非人因素。进行了多级模糊综合评判，建立了相应的对检测质量影响的理论模型。为验证所建立的数学模型的正确性和有效性，进行了数值实例计算。计算分析结果表明，本文所建立的理论分析模型是比较科学合理的，能较好地分析人的因素对检测质量的影响，为平台结构的完整性、可靠性以及剩余寿命的评估提供了基础和依据     

大连海洋产业发展分析及结构优化升级对策研究

大连市海洋经济凭借优越的资源和区位条件得到了快速发展,对国民经济的贡献愈来愈高,已成为新的经济增长点。文章深入分析大连市海洋经济发展现状以及海洋产业存在的问题,提出海洋产业结构优化升级的对策建议,助推大连海洋产业又好又快发展。     

基于广义接触模型的离散元方法及其对船体冰载荷的分析

冰载荷是影响船舶结构安全的主要环境载荷,因而确定破冰船的冰载荷特征可用于船体结构设计及船舶安全预警分析。海冰作为典型的脆性材料,可采用单元间具有黏结失效效应的离散元方法模拟其破碎行为。为有效地模拟海冰破碎的渐进过程,采用由局部黏结点组成黏结单元的广义接触模型。为分析该模型中直接决定黏结单元失效的强度参数的影响,采用海冰单轴压缩和三点弯曲试验数值模拟进行分析。通过模型试验确定了失效模型中法向黏结强度、切向黏结强度和Mohr-Coulomb准则中的接触摩擦系数的影响。将该数值模型应用于极地科学考察船"雪龙号"的平整冰区冰载荷分析中,并与船舶整体冰阻力经验公式进行了对比验证。     

Risk Based Optimal Inspection and Repair Planning for Ship Structures Subjected to Corrosion Deterioration

A framework of risk based inspection and repair planning was presented to optimize for the ship structures subjected to corrosion deterioration. The planning problem was formulated as an optimization problem where the expected lifetime costs were minimized with a eonstraint on the minimum aceeptable rehability index. The safety margins were established for the inspection events, the repair events and the failure events for ship struetures. Moreover, the formulae were derived to calculate failure probabihties and repair probabilities. Based on them, a component subjected to corrosion is investigated for illustration of the process of selecting the optimal inspection and repair strategy. Furthermore, some sensitivity studies were provided. The results show that the optimal inspection instants should take place before the reliability index reaches the minimum acceptable reliability index. The optimal target failure probability is 10^-3. In addition, a balance can be achieved between the risk cost and total expected inspection and repair costs by means of the risk-based optimal inspection and repair method, which is very effective in selecting the optimal inspection and repair strategy.     

Cost-Benefit Assessment of Inspection and Repair Planning for Ship Structures Considering Corrosion Model Uncertainty

Owing to high costs and unnecessary inspections necessitated by the traditional inspection planning for ship structures, the risk-based inspection and repair planning should be investigated for the most cost-effective inspection. This paper aims to propose a cost-benefit assessment model of risk-based inspection and repair planning for ship structures subjected to corrosion deterioration. Then, the benefit-cost ratio is taken to be an index for the selection of the optimal inspection and repair strategy. The planning problem is formulated as an optimization problem where the benefit-cost ratio for the expected lifetime is maximized with a constraint on the minimum acceptalbe reliability index. To account for the effect of corrosion model uncertainty on the cost-benefit assessment, two corrosion models, namgly, Paik＇ s model and Guedes Soares＇ model, are adopted for analysis. A numerical example is presented to illustrate the proposed method. Sensitivity studies are also providet. The results indicate that the proposed method of risk-based cost-benefit analysis can effectively integrate the economy with reliability of the inspection and repair planning. A balance can be achieved between the risk cost and total expected inspection and repair costs with the proposed method, which is very. effective in selecting the optimal inspection and repair strategy. It is pointed out that the corrosion model uncertainty and parametric uncertaintg have a significant impact on the cost-benefit assessment of inspection and repair planning.     

基于风险海洋结构物检测及维护研究进展

随着海洋石油天然气资源的不断开发,海洋结构物得到了广泛的应用。长时间持续工作于海洋环境以及一旦失效代价高昂的特点使得海洋结构物的安全问题倍加瞩目。基于风险的检测和维护将海洋结构物的风险与费用相结合,可以在满足安全要求的前提下合理地降低运营费用,是目前国际上研究领域的热点问题。通过分析基于风险的海洋结构物检测和维护的国内外研究现状,对检测及维护操作过程中的一些关键问题和目前主流的研究方法及应用情况做了概述。最后讨论了海洋结构物检测维护研究中存在的一些问题,提出了今后的研究方向。基于风险的检测和维护将是今后一个值得关注的重要课题。     

基于风险的海洋结构物无损检测功能的分级

提出了基于风险的海洋结构物无损检测功能分级方法,采用检测概率、错误识别概率和裂纹出现概率度量检测功能,并修正了错误识别概率的取值范围。根据风险值对无损检测功能进行了分级,研究了风险值随检测概率、错误识别概率和裂纹出现概率的变化规律,分析了风险值对检测费用、维修费用及失效费用的敏感性。在此基础上,将基于风险的海洋结构物无损检测功能分级方法应用于优化检测策略,用算例证明了文中所提方法的有效性。     

Shock responses of a surface ship subjected to noncontact underwater explosions

In combat operations, a warship can be subjected to air blast and underwater shock loading, which if detonated close to the ship can damage the vessel form a dished for hull plating or more serious holing of the hull. This investigation develops a procedure which couples the nonlinear finite element method with doubly asymptotic approximation method, and which considers the effects of transient dynamic, geometrical nonlinear, elastoplastic material behavior and fluid–structure interaction. This work addresses the problem of transient responses of a 2000-ton patrol-boat subjected to an underwater explosion. The KSF=0.8 is adopted to describe the shock severity. Additionally, the shock loading history along keel, the acceleration, velocity and displacement time histories are presented. Furthermore, the study elucidates the plastic zone spread phenomena and deformed diagram of the ship. Information on transient responses of the ship to underwater shock is useful in designing ship hulls so as to enhance their resistance to underwater shock damage.     

Initial post-buckling of submerged slender vertical structures subjected to distributed axial tension

This paper proposes an analytical solution for determining the initial post-buckling behaviour of submerged slender vertical steel structures. These structures may have significant bending stiffness and self-weight so that the axial force varies linearly from one end to the other. Such structures constitute main components of drilling and production platforms used for the offshore exploitation of hydrocarbons. An understanding of their structural behaviour after buckling offers opportunities for cost reduction and design optimisation. The initial post-buckling behaviour is evaluated by retaining non-linear curvature terms and using an expansion in series to reduce the governing equation to a set of linear ordinary fourth order differential equations, which are then solved sequentially by power series functions. The paper also presents results from buckling and non-linear large deflection finite element analyses. The numerical results validate and establish a range of application for the analytical formulation. This solution technique is employed to explore the behaviour of slender structures dominated by geometrical (tension) or flexural stiffness.     

低速运动船只撞击埋置框架结构动力分析模型

通过引入合理的撞击模型,建立了水面运动船只低速撞击埋置框架结构的传递矩阵-节点耦合矩阵动力分析模型。该模型可模拟船只与结构在撞击过程中的短暂脱离,并分析撞击力时程曲线和整个撞击系统的动力响应。与有限元方法的比较验证了结构传递矩阵-节点耦合矩阵动力分析方法的有效性。不同于规范计算方法,分析发现撞击过程中的最大撞击力不仅与船只的初始动能有关,还受船只与结构间的接触刚度及结构的自身刚度影响,这两种刚度越大,则最大撞击力也越大,撞击持续时间则越短,而撞击力时程曲线的振荡越明显,甚至在船只撞击结构后的很短时间内就可能产生较大的撞击力峰值。     

Feedforward and feedback optimal control for offshore structures subjected to irregular wave forces

This paper studies the vibration control of a jacket-type offshore platform with an active mass damper (AMD) and presents a feedforward and feedback optimal control (FFOC) law. The linearized Morison equation is employed to estimate the wave load. The offshore structure is simplified into a single degree of freedom (SDOF) system. The original vibration control is formulated as the optimal control for a linear discrete-time system affected by external disturbances with known dynamic characteristics but unknown initial conditions. We give the existence and uniqueness conditions of the FFOC law. Simulation results show that, compared with the classical state feedback optimal control (CFOC) law, the presented control scheme is more efficient in reducing the displacement and velocity of the offshore structure subjected to irregular wave forces.     

我的海洋浪花飞溅区腐蚀情缘

作者回顾了近50年的科研工作生涯,特别是对海洋浪花飞溅区构筑物腐蚀防护的研究,以及我国浪花飞溅区腐蚀防护的重要事件,总结了相关工程经验。同时,对浪花飞溅腐蚀防护的未来前景进行了展望。