不锈钢海洋微生物腐蚀研究

概述不锈钢微生物腐蚀的国内外研究现状,阐述微生物腐蚀的研究方法及不锈钢微生物腐蚀模型,并对未来的研究重点进行展望。     

煤炭装卸设备钢结构安全监测方法

根据在实践中形成的一套完整的检测方案,对运行状态下的煤炭装卸设备钢结构关键部位进行检测和监测,获取其状态信息,综合设备在使用中的动态反馈信息,建立钢结构安全运行档案,对设备进行分类管理,防止其发生机械事故.     

Analysis of corrosion risk due to chloride diffusion for concrete structures in marine environment

The chloride-induced steel corrosion is one of the main causes of deterioration for reinforced concrete structures exposed to marine environments. The chloride ingress into reinforced concrete structures is even more complex since it depends on random parameters linked to transport and chemical properties of materials, which results in variability of corrosion initiation. This variation raises the need of statistical approaches to evaluate the risk of corrosion initiation due to chloride ingress. To address this issue, we use sensitivity analysis to identify the influence of input parameters on critical length of time before corrosion initiation predicted by our chloride diffusion model. Exceedance probabilities of corrosion initiation time given that input parameters exceed certain thresholds were also calculated. Results showed that the corrosion initiation time was most sensitive to: chloride effective diffusion coefficient D_e in concrete, that is a parameter controllable by relevant stakeholders; surface chloride concentration C_s, a non-controllable parameter depending on surrounding conditions. Reducing the chloride diffusion coefficient enables us to postpone the maintenance of structures. However, the interaction between controllable parameters and non-controllable surrounding conditions was revealed influential on the reliability of results. For instance, the probability that corrosion initiation time exceeds 15 years given an effective diffusion coefficient (D_e) equal to 0.1 × 10⁻¹² m²⋅s-1 can vary from 19 to 41% according to stochastic variations of chloride concentrations (C_s) values. Postponing the corrosion initiation time was combined with a decreasing probability of its occurrence.     

Additive manufacturing of miniature marine structures for crashworthiness verification: Scaling technique and experimental tests

Undoubtedly, the main advantage of the additive manufacture technology is to allow building miniature structural parts with a large degree of complexity such as to replicate structural details of real-scale marine structures. This work presents a new technique for reproducing the structural response of large-scale thin-walled metallic structures when subjected to crushing loadings by using scaled-down additive manufactured models. This technique couples scaling laws for strain rate sensitive materials and a thickness distortion technique based on the structural collapse mode. In order to validate this coupled technique, the structural response of a large-scale crushing test of a web girder structure was experimentally replicated by using a 1/40 scale reduction model. The results and conclusions summarize the prospects and limitations of additive manufacturing of miniature complex marine structures for structural purposes and crashworthiness verification.     

监测诊断技术在某型舰用燃气轮机维修管理中的应用

文章分析了应用振动频谱技术对舰用燃气轮机进行故障诊断的案例,提出了加强舰用燃气轮机使用管理的意见建议。实践表明,监测诊断是保障舰用燃气轮机工作可靠性的重要手段,是建立视情维修模式的有效技术支撑。     

Historical review of research on brittle crack propagation arresting technology for large welded steel structures developed in Japan with the application of Kca parameters

In response to the concern of increased risk of brittle fracture accompanying the recent enlargement of container ships, experimental research is being conducted to investigate brittle crack propagation arrest properties in Japan. The objective is to obtain the required toughness of the material to arrest brittle crack propagation in a 100-mm thick plate, which is considered to be the maximum thickness used in such applications. The use of K_ca as a method for determining arrest toughness is a main difference with respect to methodologies employed in Europe and the United States. In this review, we compare the approaches for determining brittle crack propagation arrest properties that are used in Japan with those used in Europe and the United States. Moreover, we review recent research trends, particularly with respect to the background and development of K_ca parameters.With regard to the industrial application techniques concerning arrestability of brittle crack propagation in steel plates, studies in the ship and storage tank research fields date back to after World War II, while some attention is also seen for nuclear power and line pipes. These research procedures were initially established in Europe and the United States, but was first adopted by Japan. However, soon after, Japan and the time when the research fell downward due to progress of steel manufacturing technology and defect management technology. Since then, research has actively resumed, and original contributions are being realised. The background of this work in Japan, and the creation of the K_ca concept will be explained herein. Further, the background of research on brittle crack propagation arrest properties in very large container ships, determination philosophy for deriving demand values, and ultrawide brittle crack propagation tests in the study of 75-mm thick material and their results are described. In both of the scenarios considered, i.e. one in which cracks are generated from the top of the hatch side coaming and arrested on the upper deck, and the other wherein brittle cracks occur at the upper deck end and are arrested in the hatch side coaming, the required K_ca was found to be 6000 N/mm^3/2.     

In situ colonization of marine biofilms on UNS S32760 duplex stainless steel coupons in areas with different water qualities: Implications for corrosion potential behavior

In the presence of biofilms, stainless steels （SS） exhibits an increase in corrosion potential, called ennoblement. In the present study, the corrosion potential （Eco,） behavior of the duplex SS UNS S32760 was recorded simultaneously with the in situ marine biofilm formation in two areas at Arraial do Cabo, Southeastern Brazil. The biofilm at Forno Harbor （an anthropogenically disturbed area） was characterized by higher relative abundances of Bacteria at day 2, followed by diatoms （especially Navicula sp.） on day 10 and dinoflagellates on day 18, whereas no clear trend was recorded at Cabo Frio Island （an undisturbed area）. The ennoblement of Ecor values was site-dependent. In a complementary laboratory assay, biofilms were removed and the Eco values registered in sterile conditions for the subsequent 10 days and corroborated in situ results. Understanding biofilms and SS interactions has important implications for materials science and engineering decisions as well as helping to fill in imnortant gaps in this knowledge.