10CrNi3MoV船用钢热冲压成形表层渐变微观结构与抗冲击性能

采用电子显微镜（SEM）、力学性能测试等手段,分析了10CrNi3MoV船用钢热冲压成形前后微观结构变化,及热冲压成形后材料表层渐变微观结构和里层马氏体结构产生原因与变化规律。研究表明,在热冲压成形过程中,10CrNi3MoV船用钢受急剧的冷热交互作用及高温氧化脱碳等的影响,其表层由里到表依次形成以完全马氏体、马氏体与铁素体的混合组织、铁素体组成的渐变微观结构,里层则形成以均匀的板条状的马氏体组织为主的微观结构。10CrNi3MoV船用钢热冲压成形后其表层渐变微观结构,能有效的降低结构的峰值冲击力,保证了内层强度大的马氏体材料不至于过早失效,而材料较平缓的结构峰值力及逐层失效的特点性,使热冲压成形后的成形件保持较高的吸能能力和抗冲击性能。     

10CrNi3MoV船用钢热冲压成形表层渐变微观结构与抗冲击性能

采用电子显微镜(SEM)、力学性能测试等手段,分析了10CrNi3MoV船用钢热冲压成形前后微观结构变化,及热冲压成形后材料表层渐变微观结构和里层马氏体结构产生原因与变化规律。研究表明,在热冲压成形过程中,10CrNi3MoV船用钢受急剧的冷热交互作用及高温氧化脱碳等的影响,其表层由里到表依次形成由完全马氏体、马氏体与铁素体的混合组织、铁素体组成的渐变微观结构,里层则形成以均匀的板条状的马氏体组织为主的微观结构。10CrNi3MoV船用钢热冲压成形后,其表层渐变微观结构能有效地降低结构的峰值冲击力,保证内层强度大的马氏体材料不至于过早失效,而材料较平缓的结构峰值力及逐层失效的特点,使热冲压成形后的成形件保持较高的吸能能力和抗冲击性能。     

水下爆炸载荷作用下舰船结构动响应及新型防护结构

为提高舰船的战斗力和生命力,研究水下爆炸载荷作用下典型舰船结构的损伤破坏模式以及构件爆炸变形能吸收特性乃是极其必要的。基于上述研究,并结合吸能理论,设计出4种吸能效果好、结构材料轻、制造工艺简单的舰船双层底新型防护结构形式;采用数值仿真与试验相结合的研究方法,分析新型结构形式的吸能效果,获得吸能效果较佳的舰船双层底新型防护结构形式。     

泡沫铝填充薄壁结构吸能分析

研究了4种截面形式的泡沫铝填充薄壁结构的吸能特性。采用ANSYS/LS-DYNA显式动态有限元分析软件,对结构轴向冲击过程进行仿真,给出了作用反力、吸能效率随轴向压缩位移的曲线,并讨论了截面形式、冲击速度、薄壳材料和泡沫铝密度等参数对结构吸能的影响,为合理的抗冲击结构设计提供参考。     

折叠式夹芯层结构耐撞性能研究

折叠结构是将平板按有规律的线系网格进行局部褶皱而得到的立体结构,是一种新颖的夹芯层结构,可以提高结构吸能特性,改善结构的耐撞性能。文章利用非线性软件MSC.Dytran数值仿真分析了折叠式夹芯层结构在碰撞载荷作用下的力学行为,评估其平均压皱强度及吸能特性;研究了结构参数尺寸对耐撞性能的影响。分析表明,折叠式夹芯层结构在碰撞载荷作用下具有良好的吸能特性,是理想的吸能单元;各结构参数对结构耐撞性能产生不同程度的影响,进行结构参数优化研究可进一步提高结构的吸能。     

折叠式夹芯层结构耐撞性能研究

折叠结构是将平板按有规律的线系网格进行局部褶皱而得到的立体结构,是一种新颖的夹芯层结构,可以提高结构吸能特性,改善结构的耐撞性能.文章利用非线性软件MSC.Dytran数值仿真分析了折叠式夹芯层结构在碰撞载荷作用下的力学行为,评估其平均压皱强度及吸能特性;研究了结构参数尺寸对耐撞性能的影响.分析表明,折叠式夹芯层结构在碰撞载荷作用下具有良好的吸能特性,是理想的吸能单元;各结构参数对结构耐撞性能产生不同程度的影响,进行结构参数优化研究可进一步提高结构的吸能.     

聚乳酸/碳纤维复合梯度材料在FPSO碰撞中力学性能研究

采用聚乳酸(PLA)/碳纤维复合梯度材料对FPSO舷侧立管的防护结构进行优化设计,从防护结构、立管结构和舷侧结构的损伤变形、碰撞力和吸能特性等方面验证其防护效果。研究表明：4种不同PLA/碳纤维分布方式的防护结构较低碳钢防护结构的防撞能力有较大提升;PLA/碳纤维质量分数的分布方式不同,其结构强度、应力传播和吸能特性均不尽相同,其中X型PLA/碳纤维的防护结构防撞性能相对最好,具有一定的工程应用价值。     

钢/尼龙夹层板抗爆性能研究

舰船结构在战斗中会受到炮弹与子弹的撞击,同时也面临炸药产生冲击波带来的损伤。钢/尼龙夹层板具有优良的抗爆性能,使得战舰在冲击过程中大大减少结构的破坏;钢/尼龙夹层板是一种具有较高比刚度与比强度的结构,本文使用有限元模拟软件分析比较了钢板与钢/尼龙夹层板在冲击波作用下的吸能情况和不同结构形式夹层板在相同冲击波作用下的响应情况,并将夹层板与同等质量钢板的吸能进行分析比较,结果表明钢/尼龙夹层板具有更好的吸能效果。当夹层板总厚度一定时,夹层板的厚度比与其对应的比变形之间存在幂函数的关系。     

玻璃钢船的结构特点

玻璃钢作为一种结构材料与钢材比较,具有比强度高、耐腐蚀、易成形等特点,用玻璃钢造船有着许多的优点。本文针对制造玻璃钢船的情况,对其板材、骨材、构件及其连接方法等进行了阐述。     

船用泡沫填充负泊松比蜂窝平压特性分析

为提高制备工艺性能，提出一种基于层叠构型的内凹负泊松比蜂窝结构的构型及制备方法，并对泡沫填充负泊松比蜂窝结构开展平面压缩试验研究。结果表明：泡沫填充内凹负泊松比蜂窝结构在受压时拥有较高的比吸能率，是一种吸能特性优良的复合构型。研究成果为该新型复合结构构型在船用舷侧防撞吸能结构的应用奠定理论基础。     

焊接热输入量对E36高强度钢接头金相组织及机械性能的影响

针对E36高强度钢,通过对不同焊接参数下焊接接头金相组织的变化和机械性能的影响进行分析研究,结果发现若焊接参数选择不当,焊接过程过大的热输入会造成焊接接头金相组织的变化,碳化物在晶界聚集偏析,从而极大降低了接头的冲击性能,导致冲击值极低,而抗拉强度和弯曲无明显影响.     

Structural behavior and design of high-strength steel welded tubular connections under extreme loading

The present work is motivated by the increasing need for cost-efficient solutions in offshore structural systems for wind energy production and for improvement of their structural performance. The structural behavior and design of high-strength steel welded tubular connections (yield strength higher than 700 MPa) subjected to monotonic and strong cyclic loading is investigated. In the first part of the paper, an experimental investigation is presented on high-strength steel tubular X-joints subjected to monotonic and cyclic loading far beyond the elastic limit of the material, leading to weld fracture. Two grades of weld metal material are employed in the welding process of the specimens. The experimental results indicate that the weld material grade has a significant influence on the deformation capacity of the welded connection under monotonic loading conditions, and its low-cycle fatigue life. The experimental procedure is simulated using advanced finite element models, elucidating several features of joint behavior and complementing the experimental results. Overall, a good agreement is found between numerical simulations and experimental results, in terms of both global response and local strains at the vicinity of the welds. Furthermore, the structural performance of the welded tubular joints under consideration is assessed using available design methodologies in terms of both ultimate strength and low-cycle fatigue resistance, in an attempt to validate an efficient design methodology for low-cycle fatigue. The results from this research effort are aimed at developing the necessary background for the possible use of high-strength steel in tubular steel lattice structures, particularly in offshore platforms for renewable energy production. They can also be used as a basis for the possible amendment of relevant design specifications and recommendations for including special provisions for high-strength steel structural systems.     

搅拌工具轴肩和搅拌头轮廓对铝合金搅拌摩擦焊的影响一对比研究(英文)

In marine application,marine grade steel is generally used for haul and superstructures.However,aluminum has also become a good choice due to its lightweight qualities,while rusting of aluminum is minimal compared to steel.In this paper a study on friction stir welding of aluminum alloys was presented.The present investigation deals with the effects of different friction stir welding tool geometries on mechanical strength and the microstructure properties of aluminum alloy welds.Three distinct tool geometries with different types of shoulder and tool probe profiles were used in the investigation according to the design matrix.The effects of each tool shoulder and probe geometry on the weld was evaluated.It was also observed that the friction stir weld tool geometry has a significant effect on the weldment reinforcement,microhardness,and weld strength.     

船用EH36高强钢无缝药芯焊丝焊接接头组织和冲击韧性研究

本文以SRSF501无缝药芯焊丝在船用EH36高强钢中的焊接应用为目的,研究了国产无缝药芯焊丝SRSF501在船用EH36高强钢焊接中的组织和冲击韧性。通过试验表明：SRSF501焊接EH36钢接头各区域的冲击性能均满足船级社要求；多层多道焊时,焊缝组织由粗大的柱状组织和细小的等轴晶组织组成,底层焊缝和末道焊缝柱状晶区域较大；盖面层两侧接头热影响区存在粗晶区,其它位置接头的热影响区不存在粗晶区；焊接接头中熔合线外2mm处,晶粒最细,冲击韧性最好。     

基于多种失效模式SPS复合钢板替换船用钢板的优化设计

在SPS复合钢板的设计中获取不同的失效模式。以减重为目标,应用序列二次规划法对SPS复合钢板进行等效船用钢板的优化设计,同时对SPS复合钢板进行多目标优化,应用层次分析法定各目标的权重。在这两种优化方法的基础上,对船用钢板与SPS复合钢板进行了屈曲、弯曲对比数值分析,同时将结果与理论计算结果对比分析。结果表明,SPS复合钢板重量能够减轻37%以上,刚度增加两倍多,但厚度增加70%。     

耐蚀金属复合材料在海洋环境中应用的可行性研究

以不锈钢/碳钢金属复合材料为例,探讨耐蚀金属复合材料在海洋环境中长期使用的可行性。结果表明,耐蚀金属复合材料在海洋大气区和浪溅区时具有良好的耐蚀性,使用效果显著;但当耐蚀金属复合材料在水位变动区使用时,必须采取有效措施(如阴极保护)消除复合材料基材与复材之间电偶腐蚀,以保证复合材料在该区域的使用效果。     

船用氮气储存罐的筒体和封头焊接工艺分析

Q345R钢是普通低合金高强度钢,广泛的用于压力容器制造行业。其S、P含量控制较严,焊接性较好,但是由于含有一定量的合金元素,淬硬、冷裂倾向都比低碳钢大一些。通过船用氮气储存罐的筒体和封头环焊缝的焊接,分析了Q345R钢的化学成分和机械性能,通过选用合理的焊接材料、坡口形式、焊接方法、焊接工艺来保证储存罐的焊缝质量。     

船舶电力系统高次谐波危害与抑制研究

在陆上高次谐波对电网的危害,近年来已逐渐被重视。而船舶电网由于非线性负荷和冲击负荷的增加,高次谐波比陆上更严重,但没有得到重视。船舶电力系统中高次谐波的产生原因主要是变流装置的广泛使用。船舶高次谐波的危害是多方面的,最主要的危害是影响船舶电气设备的正常工作和缩短船舶电气设备的使用寿命,比较严重的危害有电网产生谐振过电压击穿绝缘,给保护装置和自动化装置提供误信号使其产生误动作。高次谐波的抑制方法主要有装设滤波器和谐波抵消法。许多新型用电设备对船舶电能质量提出了更高的要求,因此重视船舶电网高次谐波问题很有必要。     

Compressive strength of tubular members with localized pitting damage considering variation of corrosion features

Localized pitting corrosion often occurs on marine and offshore structures in the form of patch corrosion with great uncertainties in the location, size and shape. The variation of corrosion features affects ultimate strength of tubular members significantly, but it is still not well understood. This paper presents a numerical study on tubular members of diverse slenderness ratios to clarify the localized pitting effect on ultimate strength. Numerical analyses were performed based on novel models of pitted members that were calibrated against benchmark column tests. Corrosion pits were randomly introduced on the local outside surfaces of members via stochastic simulation, forming corrosion patches varied in the location, size and shape. Numerical results obtained were regressed to propose a unified empirical formula to predict ultimate strength. It turned out that the shape of the corrosion patch has a significant influence on the ultimate strength. The shape change of the patch can alter failure modes of medium length columns. The reduction of ultimate strength is closely related to the shape ratio of the patch besides the volume loss of corroded material. The unified empirical formula incorporating the shape ratio and the volume loss shows a good ability to predict the experimental results.