关于客车雨刷器执行机构失效问题的分析与解决

文章针对客车前挡风玻璃上的雨刷器各部件由于安装精度不够,造成雨刷器的执行机构失效,表现形式为烧保险、烧继电器、烧电机、烧电线等现象,造成车辆在下雨天不能正常使用,或根本不能使用,直接导致汽车客车晚点、停运、甚至引发交通事故,给运输企业、承包单位、乘客、社会带来较大的经济损失和社会问题,进行了分析与研究,并从汽车生产过程...     

Analytical study on controlled lateral thermal buckling of antisymmetric mode for subsea pipelines triggered by sleepers

Subsea pipelines exposed to high temperature and high pressure (HTHP) conditions is susceptible to lateral buckling. In order to control lateral buckling, engineered buckle initiators, such as sleepers, are introduced to initiate planned lateral buckles along the pipeline at specific locations in order to ensure that the stress in each lateral buckle remains acceptable. In this study, taking the interaction of adjacent buckles into account, analytical solutions of antisymmetric lateral buckling mode triggered by sleepers are derived. With the proposed formulations, the method to obtain the accurate locations of lateral displacement amplitude and maxima of bending stress is presented and discussed. And a detailed comparison between symmetric and antisymmetric mode of lateral buckling triggered by single sleeper is presented. Moreover, the influence of the sleeper spacing on controlled lateral buckling behaviour with the consideration of axial interaction between adjacent buckles is conducted. Finally, a detailed analysis about the influence of the sleeper height, lateral frictional coefficient and submerged weight of the pipeline on the controlled post-buckling behaviour is presented. Our results show that, for smaller sleeper friction or smaller sleeper height, the symmetric mode is more likely to happen, while the antisymmetric mode is prone to occur for larger sleeper friction and larger sleeper height. One effective method to reduce displacement amplitude and maximum stress is to decrease the sleeper spacing. The minimum critical temperature difference decreases with increasing sleeper height and increases with increasing lateral friction coefficient or submerged weight of the pipeline. And an alternative way to reduce the maximum stress is to reduce the lateral friction coefficient or submerged weight of the pipeline even though the displacement amplitude increases.     

8孔110m跨简支曲弦钢桁梁顶推施工技术

京张高铁官厅水库特大桥主桥8孔110 m跨简支曲弦钢桁梁采用支架拼装+计算机控制多点同步顶推施工技术架设。与常规连续钢桁梁顶推不同,简支钢桁梁顶推施工前需先变成连续结构,变成连续梁后,存在10.8 m和12.8 m两种节间长度,为不等节间顶推施工。结合工程实践,对顶推施工过程中的如何降低摩擦系数、如何使滑块实际受力值与计算值相吻合、顶推方式创新的问题进行了探讨。     

Underactuated control and analysis of single blade installation using a jackup installation vessel and active tugger line force control

The assembly and installation costs account for a large share in the overall expenditures of an offshore wind farm project. Single blade installation is suitable for large scale wind turbines due to the lower crane capability requirement and lower transportation time. By introducing active tension control on the tugger lines, an automatic single blade installation approach can accomplish operations in higher sea states, reduce the waiting-on-weather time, and improve the operational efficiency. Compared to early research, a more complicated control objective is achieved in this paper, i.e., a two-tugger-line configuration is applied to stabilize the suspended blade in three degrees of freedom during crane rotation and blade root-hub mating processes. The pulleys on the crane boom, i.e., the ends of the tugger lines, are assumed to be fixedly placed, resulting in tugger line time-varying inclinations. A novel backstepping-like controller is designed and proved. It is able to stabilize the blade around its equilibrium and make it track the desired path. Sensitivity studies are conducted to evaluate the influence of the tugger line inclinations. In addition, the influence of the installed blades on a three-blade horizontal wind turbine with a monopile foundation is discussed. The proposed active control setup improves the installation success rate and reduces the risks for blade impacts that may occur during mating.     

海底水平阵性能分析

矩阵滤波技术是通过设计一个全局优化的空域滤波器,使得该滤波器对不感兴趣的区域响应尽可能小,对感兴趣的区域响应尽可能不失真,基于该原理可以消除阻带区域的干扰噪声,并且保留通带区域的弱目标信息,是一种比较实用的弱目标定位检测方法,但其定位精度受很多因素制约。本文首先介绍最小二乘矩阵滤波器的设计原理、匹配场噪声抑制原理及归一化通阻带误差的计算公式,然后针对矩阵滤波器应用于海底水平阵的方法,分别从声源频率、阵元个数和阵元间距3个方面分析研究影响海底水平阵性能的因素,总结出使滤波器能够达到比较好的滤波状态时的因素条件,进而提高滤波性能。     

钢套钢直埋蒸汽管道技术在跨越河道中的应用

文中以国电驻马店热电厂配套长输蒸汽管线跨越该城市重点河道的工程为例,通过计算高支架最大间距并结合大推力固定支架的结构特性,优化了设备的选型与布置,并解决了埋地弯头热补偿问题,对蒸汽管道跨越河道工程中普遍存在的高支架设置过于紧凑、大推力固定支架难处理等技术难点提供的有效解决方案。讨论了钢套钢直埋蒸汽管道工程中管件的选配、布置以及各个施工细节的处理方法。     

浅谈提高可调桨修理的检测精度及检测装置设计研究

文章针对可调桨桨叶在受到重大损伤经焊补修复后对桨叶螺距和可调桨静平衡的检测进行了探索和研究,设计适合可调桨修理专用的检测装置,成功地消除可调桨所存在的螺距和静不平衡量偏差超差的缺陷,有效地提高了可调桨修理的检测精度,取得了显著的效果。     

长江下游地区挖入式港池口门宽度的计算方法

受长江航道的自然地形水深和南京长江大桥通航净空的限制,港口物流服务的腹地纵向延伸和广域化辐射受到较大阻碍,因此,在长江下游河段新建的港口宜尽量兼备承接上游来船转运出海的功能和由海轮转驳江轮的功能。现行规范对于挖入式港池宽度已有较为详细的规定,但对于船舶进出于两码头之间的挖入式港池口门宽度还没有明确的规定和要求,从航道角度出发,引入航行漂角和偏航角概念,着力于阐述船舶进出于两码头之间的挖入式港池口门宽度的计算确定方法。     

基于FLUENT的轴流式波浪能发电装置叶片角度设计

小型轴流式叶轮波浪能发电设备作为一种可行方案,减少了传统海上浮标维护的周期及成本.轴流式波浪能发电装置的叶片角度是关系到发电效率的核心问题之一,通过使用FLUENT软件对海上浮标的轴流式水轮机叶片安装夹角间的变化进行模拟计算,得出水叶轮在不同的安装角度情况下受力、转矩等数据,进而分析叶片安装角度对叶轮发电效率的具体影响.仿真结果为实际叶片的设计提供了指导.     

复杂地质燕尾段隧道施工技术

宜万铁路高阳寨隧道长4730m,其中出口端为双线大跨加燕尾段,穿越坡积体、堆积体、岩溶和富水的断裂破碎带等地质复杂地段,通过对该隧道大跨加燕尾段的施工方案制定和实施,介绍在复杂地质地段的大跨隧道的施工技术及施工注意事项。