海上横向补给高架索道系统的动力学方程

在对高架索道的曲线坐标系进行理论推导和对高架索道受力进行分析的基础上,建立了海上横向补给高架索道系统的动力学方程,理论上可求出其相应的动力学响应.     

横向补给系统高架索的参激振动研究

考虑了集中质量、轴向运动等因素对系统动力学行为的影响,建立了海上横向补给系统高架索的面内振动的连续模型。利用Galerkin方法对高架索偏微分模型进行模态离散,得到了1、2阶模态耦合的高架索系统的标准的动力学控制方程,利用多尺度方法对动力学方程进行渐近分析。对系统存在的两类参数激励共振进行了数值分析,得到了系统时间历程曲线、相图以及频谱图,研究结果表明高架索横向振动存在混沌等复杂的动力学特性。     

A Review of Dunes in Today's Society

Prior to Superstorm Sandy, the importance of dunes had been widely overlooked in many coastal societies. However, the stark contrast between New Jersey coastal areas that were and were not protected by dunes has created a positive paradigm shift in coastal law and public dune opinion. Government officials are mandating the construction of artificial dunes along New Jersey's coast, but it is necessary for communities to first understand the complex nature of these unique systems. With the proper knowledge, a dune can be both a protective structure as well as a working habitat that will ultimately better protect upland infrastructure and improve beach health. However, a general lack of terminological consistency among formal media and governing entities makes properly quantifying and assessing dune health difficult and unwarranted ecological conclusions inevitable. Here, dune terminology, “blowout,” “washout,” and “bowling” is clarified and defined and the dynamic nature of dunes is explained.     

某型综合补给船补给门架的设计

补给门架作为横向补给装置特殊的基座,其设计的好坏对实现补给装置的功能至关重要。该文结合某型综合补给船,阐述了门架的外形及尺寸确定、门架受力分析、门架结构设计、门架强度和振动有限元分析的整个补给门架设计的一般过程。     

两船在波浪中耦合运动的三维频域理论研究

本文采用三维势流理论求解两船在波浪中相互干扰的耦合运动。基于源分布方法，两船船体表面被划分成若干面元，在每一面元上进行等源强分布。为了验证该理论以及算法的可行性，计算了有限水深中两圆柱的水动力干扰，其数值计算结果与其他理论结果吻合较好。其次计算了两船在波浪中无航速与有航速情况的水动力干扰，其结果与单船结果以及双船试验结果进行比较。同时深入研究了纵横向间距以及航速变化对水动力干扰的影响，得出间距与航速不仅是水动力干扰的重要参数，而且对两船中的小船影响尤为重要。本文的研究提出了一种有效而又简单的方法预报两船在波浪中的耦合运动，为分析海上航行补给所涉及的水动力问题提供了有效的手段。     

Modeling Potential Impacts of Beach Replenishment on Horseshoe Crab Nesting Habitat Suitability

Beach replenishment has been proposed to increase nesting habitat for horseshoe crabs, but its environmental consequences may compromise the egg development and viability of this declining species. Horseshoe crab habitat requirements were used to build a habitat suitability model in STELLA to predict the potential impacts of beach replenishment on horseshoe crab eggs. A habitat suitability index (H.S.I.) comprised of six variables (dissolved oxygen, sediment grain size, sand temperature, sand moisture, wave energy, and salinity) was developed and compared between replenished and natural beaches. Sediment grain size and dissolved oxygen were higher in the natural beach, whereas sand temperature and moisture were higher in the replenished beach, resulting in significantly higher suitability of the natural beach (p = 5.39 × 10^?15, df = 30). The model was most sensitive to air temperature, rainfall, tide, and sediment grain size. This model is useful for understanding the processes affecting horseshoe crabs and predicting impacts of coastal management activities on habitat suitability. Based on the results of this model, beach replenishment is not recommended for increasing or improving horseshoe crab habitat, unless care is taken to match fill sediment to natural grain size and color.     

基于模糊评价的补给策略优选研究

通过分析补给策略选择影响因素,针对补给策略综合评价问题,文章利用模糊评价方法,给出一种定性判断和定量分析相结合的评价模型,最后运用实例计算,证明模型在解决补给策略优选问题上的科学有效性。     

高架索航行补给中船舶在波浪中的运动性能研究

采用三维势流理论计算高架索航行补给中两船在波浪中的运动响应,将船体周围流场速度势分解为波浪入射势、自身绕射势、相邻船体的存在产生的绕射势、自身辐射势和相邻船体运动产生的辐射势,通过源汇分布法进行求解;对高架索索道上的恒定张力在耦合方程中表示为高架索瞬时张力系数矩阵;求解两船体在规则渡中的联立运动方程可得两船的运动响应.通过计算结果与高架索航行补给中两船运动响应的试验结果进行比较,吻合良好,说明文中的计算方法是可行的,在此基础上,对不同高架索恒定张力和不同浪向角条件下的接受船运动幅值响应进行计算并讨论.最后得出结论.     

舰船海上纵向补给装置液压系统的模糊故障树分析

在建立舰船海上纵向补给装置液压系统故障树的基础上,对液压系统进行模糊故障树分析,采用参照函数为正态型的L-R模糊数来描述各底事件发生的概率,推导出液压系统不能正常工作顶事件发生的模糊概率及其隶属函数分布,为提高系统的可靠性、改进结构设计提供了理论依据.     

基于视觉的集装箱海上并靠吊装位姿识别

舰船在远海进行并靠补给时受波浪影响两船之间会产生无规律的相对运动，给补给集装箱吊装工作带来了很大挑战，急需一种能够在较高海况下辅助人工的自动化吊装系统。针对这一问题，本文提出了一种基于单目视觉和ArUco标志点相结合的集装箱位姿检测方法。首先，介绍了带有视觉系统的并联吊装系统主要组成部分，简要分析了控制流程及方法；然后，根据实际集装箱码放流程，设计了适用的ArUco标志点布放和检测方案，介绍了相机标定、ArUco标志点检测及集装箱位姿估计方法；最后，搭建模拟试验平台测试视觉位姿识别的精度、速度和不同光照条件下的鲁棒性。试验结果表明，在普通工控PC平台上，最低识别速度在15Hz以上，姿态角平均误差为 ，位移量平均误差为 ，可以满足并靠吊装要求。