纵向弯矩下材料随机特性对复合材料船体可靠性的影响

The effects of stochastic characteristics of materials on the reliability of ship hulls made of composite materials under longitudinal moment were extensively studied using reliability and sensitivity calculations of a composite ship hull which was sagging.The reliability indices and failure probabilities of the ship in three kinds of failure modes (buckling,material failure,and ultimate collapse) were calculated by the surface response method and JC method.The importance factors of random variables in stochastic models,such as the model errors in predicting the ultimate longitudinal strength of ship and the longitudinal bending moment that the ship withstands,as well as the stochastic characteristics of materials in the models used,were calculated.Then,the effects of these random variables,including the stochastic characteristics of materials on the reliability index and the failure probability of ships which were sagging,were discussed with their importance factors.The results show that the effects of stochastic characteristics of materials on the reliability of ship hulls made of composite materials should be considered during the reliability assessment of composite ships.Finally,some conclusions and recommendations were given for high-speed ship design and safety assessment.     

Research on the strategy of underwater united detection fusion and communication using multi-sensor

In order to solve the distributed detection fusion problem of underwater target detection, when the signal to noise ratio (SNR) of the acoustic channel is low, a new strategy for united detection fusion and communication using multiple sensors was proposed. The performance of detection fusion was studied and compared based on the Neyman-Pearson principle when the binary phase shift keying (BPSK) and on-off keying (OOK) modes were used by the local sensors. The comparative simulation and analysis between the optimal likelihood ratio test and the proposed strategy was completed, and both the theoretical analysis and simulation indicate that using the proposed new strategy could improve the detection performance effectively. In theory, the proposed strategy of united detection fusion and communication is of great significance to the establishment of an underwater target detection system.     

The motion analysis of fire video images based on moment features and flicker frequency

In this paper, motion analysis methods based on the moment features and flicker frequency features for early fire flame from ordinary CCD video camera were proposed, and in order to describe the changing of flame and disturbance of non-flame phenomena further more, the average changing pixel number of the first-order moments of consecutive flames has been defined in the moment analysis as well. The first-order moments of all kinds of flames used in our experiments present irregularly flickering, and their average changing pixel numbers of first-order moments are greater than fire-like disturbances. For the analysis of flicker frequency of flame, which is extracted and calculated in spatial domain, and therefore it is computational simple and fast. The method of extracting flicker frequency from video images is not affected by the catalogues of combustion material and distance. In experiments, we adopted two kinds of flames, i.e. , fixed flame and movable flame. Many comparing and disturbing experiments were done and verified that the methods can be used as criteria for early fire detection.     

Numerical analysis of the high skew propeller of an underwater vehicle

A numerical analysis based on the boundary element method (BEM) was presented for the hydrodynamic performance of a high skew propeller (HSP) which is employed by an underwater vehicle (UV). Since UVs operate at two different working conditions (surface and submerged conditions), the design of such a propeller is a cumbersome task. This is primarily due to the fact that the resistance forces as well as the vessel efficiency under these conditions are significantly different. Therefore, some factors are necessary for the design of the optimum propeller to utilize the power at the mentioned conditions. The design objectives of the optimum propeller are to obtain the highest possible thrust, minimum torque, and efficiency. In the current study, a 5-bladed HSP was chosen for running the UV. This propeller operated at the stern of the UV hull where the inflow velocity to the propeller was non-uniform. Some parameters of the propeller were predicted based on the UV geometrical hull and operating conditions. The computed results include the pressure distribution and the hydrodynamic characteristics of the HSP in open water conditions, and comparison of these results with those of the experimental data indicates good agreement. The propeller efficiency for both submerged and surface conditions was found to be 67% and 64%, respectively, which compared to conventional propellers is a significantly higher efficiency.     

Sensitivity analysis and dynamic modification of modal parameter in mechanical transmission system

Sensitivity analysis is one of the effective methods in the dynamic modification. The sensitivity of the modal parameters such as the natural frequencies and mode shapes in undamped free vibration of mechanical transmission system is analyzed in this paper. In particular,the sensitivities of the modal parameters to physical parameters of shaft system such as the inertia and stiffness are given. A calculation formula for dynamic modification is presented based on the analysis of modal parameter. With a mechanical transmission system as an example, the sensitivities of natural frequencies and modes shape are calculated and analyzed. Furthermore, the dynamic modification is also carried out and a good result is obtained.     

Underwater simultaneous localization and mapping based on forward-looking sonar

A method of underwater simultaneous localization and mapping (SLAM) based on forward-looking sonar was proposed in this paper. Positions of objects were obtained by the forward-looking sonar, and an improved association method based on an ant colony algorithm was introduced to estimate the positions.In order to improve the precision of the positions, the extended Kalman filter (EKF) was adopted. The presented algorithm was tested in a tank, and the maximum estimation error of SLAM gained was 0.25 m. The tests verify that this method can maintain better association efficiency and reduce navigation error.     

响应面法模拟轴肩和搅拌针形状对铝合金搅拌摩擦的影响(英文)

The present paper discusses the modeling of tool geometry effects on the friction stir aluminum welds using response surface methodology. The friction stir welding tools were designed with different shoulder and tool probe geometries based on a design matrix. The matrix for the tool designing was made for three types of tools, based on three types of probes, with three levels each for defining the shoulder surface type and probe profile geometries. Then, the effects of tool shoulder and probe geometries on friction stirred aluminum welds were experimentally investigated with respect to weld strength, weld cross section area, grain size of weld and grain size of thermo-mechanically affected zone. These effects were modeled using multiple and response surface regression analysis. The response surface regression modeling were found to be appropriate for defining the friction stir weldment characteristics.     

The measure and decision of technical risk in the development of naval vessels

The risks in development of navy vessels were explored, The resources of technical risk in the design and development of vessels were mentioned, It was pointed that technical risk dominated the other risk components. Based on the writers＇ understanding and experience from risk analysis and risk ,nanagement to the development of a navy vessel, four measure indexes of technical risk were presented. The decision criteria and the rules corresponding to the indexes were estahlished by the statistic information,     

新建半潜运输船在张力腿平台运输方面的应用研究(英文)

Transportation of tension leg platform(TLP) structures for a long distance has always been associated with the use of a heavy semi-transport vessel.The requirements of this type of vessel are always special,and their availability is limited.To prepare for the future development of South China Sea deepwater projects,the China Offshore Oil Engineering Corporation has recently built a heavy lift transport vessel-Hai Yang Shi You 278.This semi-submersible vessel has a displacement capacity of 50k DWT,and a breath of 42 meters.Understanding the vessel’s applicability and preparing it for use in future deepwater projects are becoming imminent needs.This paper reviews the current critical issues associated with TLP transportation and performs detailed analysis of the designed TLP during load-out and transportation.The newly built COOEC transportation vessel HYSY 278 was applied to dry transport of the TLP structure from the COOEC fabrication yard in Qingdao to an oil field in South China Sea.The entire process included the load-out of the TLP structure from the landsite of the fabrication yard,the offloading and float-on of the platform from the vessel,the dry transport of the TLP over a long distance,and the final offloading of the platform.Both hydrodynamic and structure analysis were performed to evaluate the behavior of the transport vessel and TLP structure.Special attention was paid to critical areas associated with the use of this new vessel,along with any potential limitations.The results demonstrate that HYSY 278 can effectively be used for transporting the structure with proper arrangement and well-prepared operation.The procedure and details were presented on the basis of the study results.Special attention was also given to discussion on future use based on the results from the analysis.     

FPSO外输系统维修策略研究

浮式生产储油轮(FPSO)是当今海洋石油天然气开发的主要设备之一。针对外输系统作为FPSO重要的一个子系统,但其传统维修策略过于依赖经验的缺陷,从可靠度角度出发,通过对失效模式和失效概率的分析从而确定较为合理的检修周期和大修周期。采取失效模式和效果分析（FMEA）方法确定主要失效模式及其关系,再利用动态故障树分析（DFTA）方法获得最小割集及相应故障时间,最后通过成组维修理论从全局最优化,经济性角度确定大修周期约为3.23年。经过与工程实际数据的对比,验证了该方法的可行性和适用性。     

基于隐患分析的海洋钻修机井架及底座安全评估

针对海洋钻修机井架及底座的安全评估方法的局限性,采用安全检查表法(SCL)、故障类型及影响分析法(FMEA),以及事故树分析法(FTA)从设备隐患的角度出发对井架进行全面的安全评价,结果表明:SCL可有效识别井架及底座存在的隐患,隐患发生在二层台及井架主体部位居多,安装不合理为最主要的隐患形式;FMEA方法可识别出井架及底座常见故障类型、原因,以及影响;采用FTA方法分析梳理出井架及底座常见事故产生的原因。     

共模故障分析在起落架系统中的应用研究

共模故障（COMMON MODE FAULT,CMF）广泛存在于复杂系统中,研究如何对系统中可能引发共模故障的故障状态进行识别、提出预防措施、降低共因故障发生概率,成为当今可靠性安全性领域重要的研究方向。共模故障分析（COMMON MODE FAULT ANALYSIS,CMFA）是一种用于复杂系统可靠性、安全性和风险性评价的方法,是故障模式与影响分析和故障树分析的补充,此方法可以用来检验系统各组成部分之间是否满足独立性要求,确定共模故障条件下对系统失效的概率。通过共模故障分析方法在某型民机起落架应用过程的分析研究,为今后此分析方法的应用提供参考。     

FMEA在船舶分油机中的应用

以船舶分油机为研究对象,应用故障模式及影响分析方法(FMEA)确定出分油机的各种可能故障模式、故障原因和故障影响.同时计算出各故障的风险度,并依此对故障进行了分级,找出对分油机危害严重的故障.最后根据分析结果提出提高其可靠性的参考措施.本文研究能对其他的船舶设备应用FMEA进行可靠性分析提供有效的参考.     

全球FPSO船型开发领域核心技术的演化分析

以国内外专利数据为分析对象,采用专利计量分析的技术方法深入研究浮式生产储油卸油装置(FPSO)开发技术的演化态势,对FPSO船型开发领域的核心专利进行分析,总结出FPSO船型开发的发展路线.结果表明:当前FPSO船型开发领域的主要研究方向是旧船改造、新概念FPSO和通用FPSO.旧船改造的技术点主要聚焦于超大型船舶设计;新概念FPSO的技术点主要集中于浮体形状设计、上部甲板大型化和刚性立管作业问题;通用FPSO的技术点主要侧重于标准化船壳设计、模块化FPSO设计和FPSO一体化建造,未来企业可考虑在模块化FPSO的上甲板承载与布局、管线布置、生活区布置、减摇和抑制垂荡问题上进行专利布局研究.     

西非铝矾土进口海运供应链风险评估

在分析从西非到我国终端客户的铝钒土进口海运供应链(Bauxit Import Maritime Supply Chain,BIMSC)内部和外部影响因素的基础上,采用故障模式与影响分析(Failure Mode and Effects Analysis,FMEA)和模糊贝叶斯网络(Fuzzy Bayesian Network,FBN)相结合的方法,建立BIMSC风险评估方法的概念框架。采用FMEA辨识潜在的失效模式,并剖析失效原因和后果;根据失效模式潜在的因果关系建立贝叶斯网络;利用三角模糊数处理表征风险参数的不确定性,评估BIMSC风险水平,并进行敏感性分析,确定风险因子排序。研究结果表明,港口操作中的违规操作、违规指挥、货物易流态化和安全管理问题是主要的风险因素。     

FPSO外输系统动力响应及风险分析

采用水动力分析软件AQWA对由软钢臂式单点系泊FPSO和油轮组成的串靠外输系统的动力响应和安全性进行研究。基于多体方法,建立串靠外输系统的有限元模型,计算4种拖轮拉力和24种作业海况下外输系统的连接大缆张力、两浮体相对艏向角及间距的时间历程,并分析波高、流速、风速、风浪流夹角、连接大缆长度等因素对系统动力响应的影响及动力响应特性。此外,还开展了串靠外输系统的风险分析,计算不同海况下连接大缆失效、船体碰撞和过分相对艏向运动的发生概率。研究结果对串靠外输系统的设计和外输作业具有一定的指导意义。     

FPSO串靠外输作业水动力耦合响应分析

FPSO与穿梭油轮串靠外输作业时两船体之间的相互作用较为复杂,基于多体水动力学方法对两浮体的运动响应进行分析.应用水动力学软件ANSYS-AQWA建立耦合响应分析模型,计算单点系泊FPSO与穿梭油轮之间的水动力影响.通过时域分析得到不同风浪流组合工况下系泊锚链与浮体之间系泊大缆的张力变化曲线,分析张力及大缆的变化特性,为串靠外输作业提供参考依据.     

FPSO外输软管安装方法分析

基于企鹅浮式生产储卸油装置(Floating Production Storage and Offloading, FPSO)项目,对比不同安装方法的优缺点,采用盘卷安装法完成外输软管安装。采用盘卷安装法进行FPSO外输软管安装在国内鲜有实例,详细描述该方法的施工顺序和要点,可为其他类似项目的外输软管安装提供参考。     

FPSO global strength and hull optimization

Global strength is a significant item for floatingproduction storage and offloading （FPSO） design, and steel weightplays an important role in the building costs of FPSO. It is the maintask to consider and combine these two aspects by optimizing hulldimensions. There are many optional methods for the globalstrength analysis. A common method is to use the ABS FPSOEagle software to analyze the global strength including the rulecheck and direct strength analysis. And the same method can beadopted for the FPSO hull optimization by changing the depth.After calculation and optimization, the results are compared andanalyzed. The results can be used as a reference for the futuredesign or quotation purpose.