船型参数对骑浪/横甩薄弱性衡准影响研究

骑浪/横甩是IMO船舶第二代完整稳性的五种失效模式之一,是一种基于概率的稳性衡准,制定规范的目的是更有效地保障船舶在实海域中的航行安全,确保不发生稳性失效情况.本研究中,以IMO有关成员国提出的最新版骑浪/横甩薄弱性衡准草案为基础,基于自主开发的骑浪/横甩薄弱性衡准校核软件,针对围网渔船开展了样船计算和比较分析,研究IMO正在制定的骑浪/横甩薄弱性衡准方法对该类船型的适用情况,分析船型参数对骑浪/横甩薄弱性衡准的影响,为我国参与国际法规制定,提出针对骑浪/横甩薄弱性衡准的提案提供技术支撑和依据.     

How do economies of density in container handling operations affect ships’ time and emissions in port? Evidence from Norwegian container terminals

Efficient port services are prerequisites for competitive and sustainable maritime transports. This paper makes advances in studying the determinants of the time that ships spend in port and the associated emissions to air. We estimate a production model for cargo handling based on a unique dataset containing each port of call at the largest container terminals in Norway in 2014. In turn, we use auxiliary engine emission factors to estimate particulate matter and nitrogen oxide emissions from ships at berth, to determine how the corresponding damage costs of air pollution vary with container throughput, location, and terminal investments. We find that Norwegian container terminals operate under increasing returns to density. Small ships that unload few containers are far from reaping economies of density, leading to high marginal time requirements for container handling and consequently high marginal external costs. From a Pigouvian taxation perspective, port charges should therefore be regressive in the number of containers handled. Moreover, we find that the external costs of maritime transports are severely understated when port operations are ignored. Our model allows determining the marginal productivities of port facilities. Thereby, it is instrumental in designing port charges that are diversified according to the quantity of containers handled and the service quality (i.e., the speed of handling operations). Regarding contextual factors, we find that establishing high-frequent liner services improves the ship working rate, while simultaneous calls at a terminal impede productivity. The type of container (loading/unloading; empty/laden) also appears to influence the duration of ship working.     

基于规范方法的小水线面双体船疲劳强度研究

论文介绍了船舶结构疲劳强度评估基本原理,并对一条2200t级小水线面双体船进行规范法疲劳强度评估。针对小水线面双体船结构特点,采用规范进行疲劳载荷计算；结合全船有限元计算结果进行疲劳部位筛选；采用有限元法提取疲劳部位的热点应力,并计算疲劳部位的累积损伤度。分析计算结果,提出疲劳部位优化方案。     

船舶轴系校中计算中优化算法的应用

本文以常见船舶轴系布置为基础,建立轴系校中计算数学模型,采用智能微群优化算法数值求解该数学模型。并对某3000吨级海监船进行轴系校中计算,结果表明智能微群优化算法求解出的轴系校中参数满足中国船级社相关规定的要求,该方法可以在轴系校中计算中推广使用。     

谈港口国船舶污染物接收设施问题报告的处置

文中探讨了一起国际航行船舶关于港口国船舶污染物接收设施问题报告的调查情况,介绍了此次船舶污染物接收设施问题报告的原因分析及采取的措施,并向接收设施的提供者和使用者给出了优化建议,明确了各有关部门在港口国船舶污染物接收设施履约工作上的重点。     

破冰型大型航标船线型开发设计及破冰阻力评估研究

结合北海航海保障中心大型航标船的破冰功能需求,为本船选取合理的推进功率,对本船具有破冰功能特点的线型设计进行分析论述,同时运用破冰阻力经验公式对本船在一定冰厚和航速下的破冰阻力进行估算,结合冰池试验结果对破冰阻力数据进行对比分析,并进行冰区航行的快速性评估。     

带扰动观测器的船舶轨迹跟踪自适应动态面滑模控制

针对遭受未知外部环境扰动的三自由度全驱动船舶轨迹跟踪控制问题,设计一种带扰动观测器的自适应动态面滑模控制方法。该方法构造扰动观测器估计未知扰动,并对控制量进行前馈补偿,采用σ修正泄漏项的自适应律估计扰动观测误差的界以提高控制精度,结合动态面技术解决传统反演法的微分爆炸问题,并选取李雅普诺夫函数证明该控制器可保证闭环系统内所有信号的一致最终有界性。基于一艘供给船舶进行仿真试验,结果表明,所设计的控制器输出合理有效且跟踪精度高,在工程实际中具有一定的参考价值。     

Full six degrees of freedom coupled dynamic simulation of ship collision and grounding accidents

By taking advantage of the user-defined load subroutine (loadud) and the user common subroutine (usercomm) in LS-DYNA, the authors proposed a new coupled approach for simultaneously calculating structural damage and the planar 3DOF ship motions in ship collisions. The coupled procedure aimed at predicting the detailed structural damage together with reasonable global ship motions. This paper extends the method to consider the full 6DOF ship motions; thus, ship collision as well as grounding accidents can be properly handled. This method is particularly useful for design purposes because the detailed ship hull profile is not needed.A traditional ship maneuvering model is used for the in-plane surge, sway and yaw degrees of freedom with a series of nondimensional coefficients determined from experiments. It is assumed that the out-of-plane degrees of freedom are not coupled with the in-plane ship motions, and there is no coupling among roll, pitch and heave motions. The implementation is verified through free decay tests, and the obtained natural periods show good agreement with theoretical results.Several collision and grounding cases are simulated in which a supply vessel crashes into rigid plates with different orientations. The effects of the roll motion, the heave and pitch motions and the full 6DOF motions are studied. The results are compared with those from a 6DOF decoupled method. Ship motions through the proposed method compare reasonably well with SIMO results. It is found that several consecutive impacts may occur in the simulation of one collision case due to the periodic motions. This is not taken into account in the decoupled method, which makes this method unconservative.     

Local joint flexibility of tubular X-joints stiffened with external ring or external plates

In the present paper, the Local Joint Flexibility (LJF) of the ring-stiffened X-joints and plate-stiffened X-joints under compressive load is investigated. In the first phase, a finite element (FE) model was generated and verified with the results of available experimental tests and equations. In the next phase, a set number of 234 FE models were created to evaluate the role of the external ring size (β_r and τ_r), the external plate size (β_p and τ_p), and the connection geometry (γ, τ, and β) on the LJF factor (f_LJF). In these FE models, the weld connecting the chord and brace members was generated. The results indicated that the f_LJF of a plate stiffened joint can be down to 76% of the f_LJF of the corresponding un-stiffened joint. Also, the effect of the ring size on the f_LJF was more than the effect of the plate size on the f_LJF, because of the stiffener position. Despite the notable effect of the ring and the plate on the f_LJF, there is not any study or formula on tubular connections stiffened with ring or plate. Therefore, the FE results were used to propose two parametric formulas for determining the f_LJF in X-joints with external ring or external plate under brace compressive load. Moreover, the derived formulas were checked based on the UK DoE acceptance criteria.     

基于正交设计的船用柴油机燃烧系统参数匹配及优化

为研究柴油机燃烧系统参数匹配对柴油机动力和排放性能的影响,首先分别利用AVL_BOOST和AVL_FIRE仿真软件建立4190ZLC-2型船用柴油机整机模型和缸内燃烧高压循环模型,然后基于已建模型应用正交试验设计方法安排柴油机进气系统、喷油系统和燃烧室结构尺寸参数匹配仿真计算。研究结果表明,通过极差分析可以得出燃烧系统参数对4190ZLC-2型柴油机性能的影响主次顺序。以柴油机指示功率为评价指标时,参数组合0.26 mm-28°CA-160°-0.9-145 mm-2.6 mm-22 mm(喷孔直径-喷油提前角-油束夹角-涡流比-喉口直径-凸台高度-凹坑半径)对应的指示功率为63.40 k W,比原机仿真值高15%;以NOX排放为评价指标时,参数组合0.30 mm-24°CA-140°-0.4-135 mm-6.6 mm-14 mm(喷孔直径-喷油提前角-油束夹角-涡流比-喉口直径-凸台高度-凹坑半径)对应的NOX排放质量分数为0.015 7%,比原机仿真值低30.2%。