舰船复合材料防护结构的选择与优化

为选择与优化舰船复合材料防护结构,根据陶瓷材料的密度小、强度大、硬度高、抗冲击性能良好等特征,建立以金属为面板的金属/陶瓷复合材料和以陶瓷为面板的陶瓷/金属复合材料结构模型,研究复合材料层合板在爆炸冲击载荷下的抗冲击性能,陶瓷/金属复合材料的抗爆炸冲击性能远远优于金属/陶瓷复合材料的抗爆炸冲击性能。在此基础上,考虑复合材料层合板在防护结构中的位置,讨论不同结构参数对防护结构爆炸冲击性能的影响。研究结果表明,当复合材料层合板设置在空舱外板时,舰船的抗爆炸冲击性能相对较优。     

舰船复合材料防护结构的选择与优化

为选择与优化舰船复合材料防护结构,根据陶瓷材料的密度小、强度大、硬度高、抗冲击性能良好等特征,建立以金属为面板的金属/陶瓷复合材料和以陶瓷为面板的陶瓷/金属复合材料结构模型,研究复合材料层合板在爆炸冲击载荷下的抗冲击性能,陶瓷/金属复合材料的抗爆炸冲击性能远远优于金属/陶瓷复合材料的抗爆炸冲击性能。在此基础上,考虑复合材料层合板在防护结构中的位置,讨论不同结构参数对防护结构爆炸冲击性能的影响。研究结果表明,当复合材料层合板设置在空舱外板时,舰船的抗爆炸冲击性能相对较优。     

非均匀伴流中复合材料螺旋桨非定常空化流固耦合研究

复合材料可改善螺旋桨空化性能及振动特性,在先进海洋推进装备领域备受关注。本文基于URANS计算复合材料螺旋桨外流场,应用FEM求解桨叶结构动态响应,并将水动力载荷及结构变形实时双向传递,建立复合材料螺旋桨非定常空化流固耦合数值计算方法。精细地模拟了桨叶经过高伴流区过程中叶梢空泡的演化;叶梢最大变形量随着叶梢空泡的初生、发展而逐渐增大,在梢涡空泡形成阶段达到最大值,然后随着空泡的溃灭而减小;揭示了复合材料的应用使螺旋桨推进效率得以提高、叶梢空化得以抑制的机理,即复合材料螺旋桨在空化水动力载荷作用下产生弯扭耦合变形,自适应地调整攻角以抑制空泡发展;对比了典型空化工况下复合材料与刚性金属螺旋桨空化水动力性能的区别;与刚性金属桨相比,复合材料螺旋桨的压力脉动峰值缓和,对非均匀伴流场的适应性更好。     

海水中钢的腐蚀保护用金属包套

本文评述了37年来采用金属包套保护海水中钢结构飞溅区及潮汐区的经验.讨论了垂直结构各不同区域之间的环境腐蚀性差异以及它们之间的相互关系.包套用的耐蚀合金包括蒙乃尔(Ni-Cu)合金400,Cu-Ni合金及不锈钢.比较了这些贵重合金相对于其他保护材料(如油漆涂层、混凝土、聚合物和钢)的优缺点.     

船舶复合材料螺旋桨模型试验的特殊性分析

[目的]船舶复合材料螺旋桨比传统金属合金螺旋桨刚度低,在流固耦合作用下桨叶变形会对水动力和噪声性能带来显著影响,在开展复合材料螺旋桨模型试验时需予以特殊考虑。[方法]采用量纲分析方法,建立复合材料螺旋桨水动力与噪声性能的特殊相似关系及其换算方法。根据复合材料螺旋桨模型加工实物及其作用特点,分析可满足模型试验要求的特殊测试技术。[结果]结果表明,复合材料螺旋桨模型试验在满足金属合金螺旋桨模型试验的相似关系外,仍需满足桨叶水动力变形的相似关系。[结论]不同于传统金属合金螺旋桨,复合材料螺旋桨模型试验需获取螺旋桨的静态型值、力学性能和桨叶动态变形等信息,以此选择合理的螺旋桨试验模型缩比尺度及其材料;同时,试验中除要求保持模型与实尺度螺旋桨的无量纲进速系数相同外,还需满足刚度特性及叶梢马赫数的组合相似度。     

掺海工耐蚀剂混凝土的电通量影响因素分析

为了考察掺海工耐蚀剂混凝土的耐久性,研究了水胶比、耐蚀剂掺量和加速养护等因素对混凝土的电通量的影响。结果表明：掺加海工耐蚀剂的混凝土,水胶比在0.38~0.41时,电通量随水胶比的减小而减小;单方混凝土的耐蚀剂掺量在50~70kg之间变化时,均能满足海工高性能混凝土抗氯离子渗透性要求,且电通量随着耐蚀剂掺量的增大而减小;与标准养护条件下混凝土的电通量相比,60℃加速养护条件下混凝土的电通量偏低。     

玻璃钢船艇设计中应关注的材料特性

玻璃钢船艇设计与传统的金属材质船艇不同。玻璃钢并非是一种单一材料,而是由玻璃纤维与合成树脂复合而成的新型树脂基复合材料。在建造船体时并无已成型为固体的玻璃钢,而需由形成玻璃钢的两种原材料在复合成玻璃钢的同时成型为船体,这与传统的先有材料再加工成船体的生产工艺有本质的不同。在玻璃钢船艇设计时,有关材料的物理力学性能数据及安全系数都不是定值,它们与所采用原材料的品种、性能、规格、增强材料布置和铺层设计,以及制造企业的职工技术素质和工艺技术管理水平、质检手段等有密切关系。由于目前造船专业院校尚未设置复合材料课程,文中从复合材料的专业角度介绍了玻璃钢的材料特性,以供设计时参考。     

碳纤维复合材料在游艇制造中的应用

正碳纤维具有十分优异的力学性能,是先进复合材料最重要的增强体,通过与树脂、碳、陶瓷、金属等基体材料复合后可制得优异的碳纤维复合材料。其复合材料以轻质、高强度、高模量、耐腐蚀、耐疲劳、可设计性强、结构尺寸稳定性好和可大面积整体成型等特点,在游艇制造等众多领域得到应用。     

原油油船货油舱耐蚀钢检测技术发展研究

货油舱的服役环境复杂,对船板钢具有很强的腐蚀性,内底板主要发生点蚀,上甲板主要发生均匀腐蚀。货油舱使用耐蚀钢是涂层保护的唯一替代方案。国际海事组织和中国船级社对货油舱耐蚀钢的腐蚀检测要求进行了明确规定。内底板耐蚀钢腐蚀检测要求简单,国内研究机构已经熟练掌握,取得了较多的研究成果;上甲板耐蚀钢腐蚀检测要求复杂,国内相关的研究成果较少。设备标准化及参数统一化是上甲板耐蚀钢腐蚀检测技术的发展方向。     

耐腐蚀非晶态镍-磷合金镀层的研制及应用前景

用电沉积法获得的含9～12%磷的镍-磷合金层,为非晶态的均相结构,具有十分优越的耐蚀性能。在常温下耐盐酸腐蚀的性能优于哈氏合金;对非氧化性氯化物的耐蚀性可与金属钛相媲美;耐各种温度与浓度的热烧碱的腐蚀性能优于金属镍;对高温氟化物的耐蚀性能与蒙乃尔合金相当;对多种有机酸及大部分介质的耐蚀性远远超过常用的奥氏体不锈钢。     

B级碳素船体钢焊接接头耐蚀性研究

通过室内腐蚀挂片及电化学测量试验 ,研究了B级碳素船体钢三种常见焊接接头的耐海水腐蚀性能。结果表明 :在海水中 ,接头的焊缝区最易受到腐蚀 ,其次为母材 ,热影响区腐蚀最轻 ;几种接头相比 ,B级碳素船体钢与J4 2 2焊条匹配后焊接接头的综合耐蚀性高于其与J50 7和H0 8MnSi2A两种焊接材料匹配后接头的耐蚀性。     

316L金属波纹管腐蚀机理分析

316L不锈钢是一种耐蚀性较好的奥氏体不锈钢,用其加工制造的金属波纹管在海水环境中短时间内出现腐蚀穿孔现象,影响系统运行安全。本文通过对金属波纹管腐蚀形貌观察,对其材料的成分、金相组织、夹杂物、腐蚀产物、电化学特性和使用工况、生产工艺等方面进行检验和分析,得出了金属波纹管短时间内点蚀穿孔的原因,并提出延长金属波纹管使用寿命的方法。     

An overview of maintenance management strategies for corroded steel structures in extreme marine environments

Maintenance is playing an important role in integrity management of marine assets such as ship structures, offshore renewable energy platforms and subsea oil and gas facilities. The service life of marine assets is heavily influenced by the involvement of numerous material degradation processes (such as fatigue cracking, corrosion and pitting) as well as environmental stresses that vary with geographic locations and climatic factors. The composition of seawater constituents (e.g. dissolved oxygen, salinity, temperature content, etc.) is one of the major influencing factors in degradation of marine assets. Improving the efficiency and effectiveness of maintenance management strategies can have a significant impact on operational availability and reliability of marine assets. Many research studies have been conducted over the past few decades to predict the degradation behaviour of marine structures operating under different environmental conditions. The utilisation of structural degradation data – particularly on marine corrosion – can be very useful in developing a reliable, risk-free and cost-effective maintenance strategy. This paper presents an overview of the state-of-the-art and future trends in asset maintenance management strategies applied to corroded steel structures in extreme marine environments. The corrosion prediction models as well as industry best practices on maintenance of marine steel structures are extensively reviewed and analysed. Furthermore, some applications of advanced technologies such as computerized maintenance management system (CMMS), artificial intelligence (AI) and Bayesian network (BN) are discussed. Our review reveals that there are significant variations in corrosion behaviour of marine steel structures and their industrial maintenance practices from one climatic condition to another. This has been found to be largely attributed to variation in seawater composition/characteristics and their complex mutual relationships.     

海洋工程钢结构腐蚀防护的研究进展

钢结构在海水中腐蚀损伤具有复杂性和多样性的特点,对其进行研究存在一定的挑战性。针对海洋工程装备的腐蚀问题,对钢结构在海水中的腐蚀机理、防腐寿命预测和评估进行概述。对比涂料防腐技术、金属涂层防腐技术、电化学防腐技术发现:国外有严格的国家环保法规,国内环保立法滞后,尤其涉及到高压低温环境中应用困难。     

用于海洋结构的锌矩阵/TiO_2-WO_3纳米复合涂料微结构、机械和耐腐蚀的WO_3纳米粒子负载效应（英文）

In this study, for marine application purposes, we evaluated the effect of process parameter and particle loading on the microstructure, mechanical reinforcement and corrosion resistance properties of a Zn-TiO_2-WO_3 nanocomposite produced via electrodeposition. We characterized the morphological properties of the composite coatings with a Scanning Electron Microscope(SEM) equipped with an Energy Dispersive Spectrometer(EDS). We carried out mechanical examination using a Dura Scan hardness tester and a CERT UMT-2 multi-functional tribological tester. We evaluated the corrosion properties by linear polarization in 3.5% Na Cl. The results show that the coatings exhibited good stability and the quantitative particle loading greatly enhanced the structural and morphological properties, hardness behavior and corrosion resistance of the coatings. We observed the precipitation of this alloy on steel is greatly influenced by the composite characteristics.     

Strength and deformability of corroded steel plates under quasi-static tensile load

The objective of this study was to estimate the strength and deformability of corroded steel plates under quasi-static uniaxial tension. In order to accurately simulate this problem, we first estimated the true stress–strain relationship of a flat steel plate by introducing a vision sensor system to the deformation measurements in tensile tests. The measured true stress–stain relationship was then applied to a series of nonlinear implicit three-dimensional finite element analyses using commercial code LS-DYNA. The strength and deformability of steel plates with various pit sizes, degrees of pitting intensity, and general corrosion were estimated both experimentally and numerically. The failure strain in relation to the finite element mesh size used in the analyses was clarified. Two different steels having yield ratios of 0.657 and 0.841 were prepared to examine the material effects on corrosion damage. The strength and deformability did not show a clear dependence on the yield ratios of the present two materials, whereas a clear dependence was shown with respect to the surface configuration such as the minimum cross-sectional area of the specimens, the maximum depth of the pit cusp from the mean corrosion diminution level, and pitting patterns. Empirical formulae for the reduction of deformability and the reduction of energy absorption of pitted plates were proposed which may be useful in strength assessment when examining the structural integrity of aged corroded structures.     

Effect of WO<Subscript>3</Subscript> nanoparticle loading on the microstructural,mechanical and corrosion resistance of Zn matrix/TiO<Subscript>2</Subscript>-WO<Subscript>3</Subscript> nanocomposite coatings for marine application

In this study, for marine application purposes, we evaluated the effect of process parameter and particle loading on the microstructure, mechanical reinforcement and corrosion resistance properties of a Zn-TiO₂-WO₃ nanocomposite produced via electrodeposition. We characterized the morphological properties of the composite coatings with a Scanning Electron Microscope (SEM) equipped with an Energy Dispersive Spectrometer (EDS). We carried out mechanical examination using a Dura Scan hardness tester and a CERT UMT-2 multi-functional tribological tester. We evaluated the corrosion properties by linear polarization in 3.5% NaCl. The results show that the coatings exhibited good stability and the quantitative particle loading greatly enhanced the structural and morphological properties, hardness behavior and corrosion resistance of the coatings. We observed the precipitation of this alloy on steel is greatly influenced by the composite characteristics.     

盐水入侵与干湿交替共同作用下船闸金属结构腐蚀特征研究

河口船闸金属结构服役于盐水上溯入侵及船闸在运行过程中由于频繁灌泄水而产生的高频干湿交替腐蚀环境，船闸金属结构(闸阀门、系船设施等)在该特殊环境下的腐蚀特征尚未知。通过开展盐水高频干湿交替下钢试样腐蚀试验，分析不同氯盐浓度、干湿制度下钢试样腐蚀形貌、腐蚀速率的变化规律。在此基础上，开展聚氨酯、环氧煤沥青、氯化橡胶防腐涂料在该特殊腐蚀环境下的适应性研究。结果表明：盐水高频干湿交替作用会显著加速钢材的腐蚀速率，其加速程度随干燥时间的增大有所减小；碳钢在盐水高频干湿交替环境中的腐蚀速率为淡水环境的5.0～6.0倍，为海洋潮汐环境的1.5～2.0倍。根据各类防腐涂料在上述特殊腐蚀环境下的宏观形貌及附着力指标实测值，结合技术经济分析，建议采用氯化橡胶类涂料作为河口船闸金属结构的防腐材料。     

Axisymmetric structural behaviours of composite tensile armoured flexible pipes

To address the weight and corrosion challenge in deep-water, replacing the steel tensile armour in flexible pipes with composite materials is an alternative conceptual approach. An axisymmetric structural responses model is built for this novel composite armoured flexible pipe, with interlayer gaps that may occur in the unbonded structure considered through an iterative algorithm. The tensile strength of steel and composite armoured pipes are predicted based on different constitutive relations of steel and composite. Essential quantities are obtained, such as tensile stiffness, deformations of each layer and interlayer gaps or contact pressures. Considering the helix form of carcass and pressure armour, a finite element model is established for the verification of the theoretical model. Case study shows that the tensile stiffness of flexible pipe is overestimated with the interlayer gap ignored. Compared with steel armoured flexible pipe, the composite armoured pipe, whose tensile stiffness decreases less as external pressure increases, meanwhile has higher values of tensile ultimate strength and torsion stiffness. Some suggestions about fiber types and volume fraction for composite tensile strips are given to ensure good performance of axial tensile strength and stiffness.     

海工钢筋混凝土构造物维修技术

钢筋混凝土构造物暴露在海洋环境中容易出现钢筋锈蚀引起的耐久性破损,导致结构物整体加速腐蚀破坏,因此及时对破损钢筋混凝土构造物进行维修对延长结构使用寿命具有重要意义.海工钢筋混凝土构造物维修除了考虑修补材料一般性能以外还须考虑施工环境和耐久性问题.随着材料科技和施工技术的发展,人们研发出了适用于海洋环境的各种修补材料和施工工艺,能适用于不同的施工环境和施工要求.系统介绍和分析了目前常用于海工构造物维修中的一些维修新技术.