Time-domain numerical and experimental analysis of hydroelastic response of a very large floating structure edged with a pair of submerged horizontal plates

This paper is concerned with the hydroelastic problem of a pontoon-type, very large floating structure (VLFS) edged with the perforated plates, non-perforated plates or their combination anti-motion device both numerically and experimentally. A direct time domain modal expansion method, taking amount of the time domain Kelvin sources in hydrodynamic forces, in which the fluid flows across the perforated anti-motion plate by applying the Darcy's law, is applied to the fluid–structure interaction problem. A quarter of numerical model is built based on the symmetry of flow field and structure in hydrodynamic forces, and special care is paid to the rapid and accurate evaluation of time domain free-surface Green functions and its spatial derivatives in finite water depth by using interpolation–tabulation method. Using the developed numerical tools and the model tests conducted in a wave basin, the response-reduction efficiency of the perforated plates is systematically assessed for various wave and anti-motion plate parameters, such as plate width, porosity and submergence depth. As a result of the parametric study, the porosity 0.11 is selected as the optimal porosity, and the relationship between the porosity and the porous parameter is developed by using the least-squares fitting scheme. After simulation and verification, the dual anti-motion plates which are the perforated-impermeable-plate combination attached to the fore-end and back-end of the VLFS, are designed for more wave energy dissipation and added damping. Considering variation of the water depths in offshore, discussion on the effectiveness of these anti-motion devices at different water depths is highlighted.     

浅议“雪龙”号恢复性改造艉轴系统拆卸

"雪龙"号是我国唯一一艘极地科学考察船,国家海洋局和江南造船(集团)有限责任公司决定2013年4月起对"雪龙"号进行恢复性维修改造。该船轴系经过20年的使用磨损,已达到设计临界状态,此次轴系修理作为维修改造过程中的重点和难点,对整个工程质量和船舶航运安全有着至关重要的影响。文章对"雪龙"号基本性能、轴系技术参数等方面做了介绍,并着重对"雪龙"号艉轴拆卸过程进行了分析和研究。     

新型半挂车悬浮式牵引装置

设计出一种安装于半挂车上的悬浮式牵引装置,能使半挂车与牵引车形成弹性连接,由此提高了半挂车的行驶平顺性,特别适用于特殊易损货物的运输。并重点介绍了该装置的结构、工作原理,以及弹性元件工作参数的计算。     

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基于虚拟样机技术的汽车托森差速器蜗轮蜗杆的运动仿真方法

以托森差速器蜗轮蜗杆为例，介绍了利用Catia软件建立零件模型、装配模型和虚拟样机模型的方法，并对仿真结果进行了分析。     

舰用典型电爆装置射频干扰试验研究

舰船的射频环境异常恶劣。电爆装置作为舰载武器系统的始发能源,可能会因吸收周围射频场的能量而发生误动作。利用GTEM模拟舰船射频场环境,对舰用典型电爆装置的射频干扰敏感度进行的试验测试表明：舰船射频环境能够对安全电流较低的电爆装置造成危害。     

综合自动化改造对电容补偿装置的影响

介绍了电容补偿装置的现状,通过漕河所二次控制设备综合自动化改造前后电容运行状况,对比分析了2种保护装置的原理。通过现场数据测试,初步分析多起电容补偿装置差压保护动作跳闸的原因,并针对该现象,提出了整改建议。     

沉箱海上沉放新工艺的研究与应用

大流量高架位虹吸位置与传统的真空虹吸装置相比具有显著的优点,借助于该装置,可以把虹吸技术应用到海上沉箱灌水沉放工艺中,与其它方法相比其效益是明显的。     

最新环保入级符号对船用制冷剂的要求分析

全面地论述了各船级社最新的环保船级符号和附加符号对中央空调和冷藏设备的制冷剂的要求,为后续新船设计作参考。     

热再生养护车的设计及其工作装置驱动功率的平衡

沥青混凝土路面的养护工艺和专用设备的优劣直接关系到道路的服务质量和通车效率，采用热再生养护车是解决这一问题的良好途径。对养护车作业装置的结构设计进行技术优化和驱动功率的平衡分析是高质量养护车研发的基础和技术关键。