Semirigid Analysis of Extended End Plate Connections Based on Correlation and Sensitivity

Traditionally,semi-rigid analysis of extended end plate connections is assumed to be deterministic parameters.Most of the moment-rotation models of the joint are determined by curve-fitting and statistically regressed with the test data.Parameters of these models have little physical meaning,and the effect of correlations in the parameters is neglected.This paper deals with a semi-rigid joint of extended end plate connections based on correlation and sensitivity analysis.A numerical study was carried out and the finite element analysis was validated compared with the experimental results.The relative moment-rotation model was concluded based on correlations in parameters and probabilistic sentivity analysis.The relationship between height and width of steel beam was partial correlation.The relationship between thickness of steel beam flange and thickness of steel beam web was also partial correlation.Height and width of steel beam,and distance of upper bolts to axle wire of steel beam section were important sensitive parameters for the extended end plate connections.

Effect of End Plates on the Performence of a Wells Turbine for Wave Energy Conversion

In order to improve the performance of the Wells turbine for wave energy conversion, the effect of end plates on the turbine characteristics has been investigated experimentally by model testing under steady flow conditions. The end plate attached to the tip of the original rotor blade is slightly larger than the original blade profile. The characteristics of the Wells turbine with end plates have been compared with those of the original Wells turbine, i.e., the turbine without end plate. As a result, it has been concluded that the characteristics of the Wells turbine with end plates are superior to those of the original Wells turbine and the characteristics are dependent on the size and position of end plate. Furthermore, the effect of annular plate on the turbine performance, which encircles the turbine and is attached to the tip, was investigated as an additional experiment. However, its device was not effective in improving the turbine characteristics.

Lumbar Disc Herniation with End-Plate Fracture and Secondary Ossification Mimicking an Epidural Tumor: A Case Report

We report a unique case of lumbar disc herniation, in particular, with end-plate and surrounded by extensive ossification, mimicking a tumor with calcification. A 69-year-old female suffered from right buttock and leg pain. Computed tomography (CT) showed an intracanalar mass with calcification or ossification, which most likely originated from the vertebral body at the L1/2 level epidural space. On a T1-weighted gadolinium magnetic resonance image, the capsule of the mass was enhanced and not only the content of the mass but also that of the L2 vertebral body were partially and slightly enhanced. The final pathological diagnosis was disc herniation with end-plate fracture and secondary ossification. A combination of these pathological conditions as accompanied by both end-plate fractures and extensive secondary ossifications has not been previously reported. This rare pathological condition needs to be recognized as a differential diagnosis.

Finite element analysis on temperature field and residual stress of welding assembly for I-beam and end-plate

Based on full scale model of 1-beam and end-plate welding assembly with medium plate, welding temperature field and residual stress were simulated, infrared thermometers were employed to measure the real-time temperature Jbr verification purposes. Results show that the measured thermal cycle curves match well with the simulation result. Simulation results of welding residual stress indicate that the values of longitudinal and transverse stress on the upper surface of the plate are higher than the normal stress; higher tensile stresses exist at the end of the web weld toes and in the central area of the flange weld toes. The dangerous zones are located at the central areas of weld toes of the flange welds and near weld toes of the web welds.

Evaluation of Stiffened End-Plate Moment Connection through Optimized Artificial Neural Network

This study involves the development of an analytical model for understanding the behavior of the extended, stiffened end-plate moment connections with eight high strength bolts. Modeling of the connection as an assemblage of finite elements (FE) used for load deformation analysis, with material, and contact nonlinearities are developed. Results from the FE mathematical model are verified with results from the ANSYS computer program as well as with the test results. Sensitivity and feasibility studies are carried out. Significant geometry and force related variables are introduced;and by varying the geometric variables of the connections within a practical range, a matrix of test cases is obtained. Maximum end-plate separation, maximum bending stresses in the end-plate, and the forces from the connection bolts for these test cases are obtained. From the FE analysis, a database is produced to collect results for the artificial neural network analysis. Finally, salient features of the optimized Artificial Neural Network (ANN) via Genetic Algorithm (GA) analysis are introduced and implemented with the aim of predicting the overall behavior of the connection.

端板对Savonius风力机启动性能的影响

为探究端板对Savonius风力机启动性能的影响,利用数值模拟和风洞试验相结合的方法对比研究了端板对两叶片、三叶片Savonius风力机在不同风速下的静态启动性能,并对流场进行了分析.结果表明:对于两叶片Savonius风力机,有端板风力机较无端板风力机平均启动力矩提升了85.4%(u=8 m/s),且反向启动力矩小,但无端板风力机启动力矩波动范围较有端板风力机小;对于三叶片Savonius风力机,有端板风力机较无端板风力机平均启动力矩提升了17.9%(u=8 m/s),但有端板风力机存在反向力矩,无端板风力机较有端板风力机整体力矩波动范围小且无反向启动力矩;端板的存在改变了叶片端部的流动情况和压力分布,叶片个数不同影响规律也不同.研究结果可以为Savonius风力机的结构设计提供参考.

蜂窝梁H型柱绕弱轴向端板连接节点抗震性能研究

目的 提出一种蜂窝梁H型柱绕弱轴向端板连接节点,探究节点抗震性能及不同因素对其影响规律,为相关设计提供借鉴。方法 理论分析蜂窝梁H型柱绕弱轴向端板连接节点传力机制,建立并验证蜂窝梁H型柱绕弱轴向端板连接节点ABAQUS模型,研究端板厚度、开孔率对节点初始转动刚度、承载能力、耗能能力、延性、刚度退化及破坏形式影响规律。结果 蜂窝梁H型柱绕弱轴向端板连接节点弯矩最终由柱腹板与正向端板抗弯、柱翼缘与侧向端板抗剪承担;剪力最终由高强摩擦型螺栓连接面间摩擦力承担;端板厚度及开孔率越大,节点耗能进入蜂窝梁耗能阶段越早,连接刚度足够时节点抗震性能主要取决于蜂窝梁。结论 提出了蜂窝梁H型柱绕弱轴向端板连接节点弯矩路径传递分配系数计算方法,建议节点端板厚度应大于1倍柱翼缘厚度,开孔率取值为60%~65%。

HPC端部加强双钢板组合剪力墙的抗震性能

为研究高性能混凝土端部加强双钢板组合剪力墙受力机理及破坏形态,以轴压比、腹部普通混凝土强度等级为关键参数,设计了4片普通试件,7片HPC端部加强试件,运用ABAQUS构建其有限元模型,研究其抗震性能。结果表明:同轴压比下,HPC端部加强试件相比普通试件屈服荷载提高16.30%,峰值荷载提升13.40%;随着轴压比提高,HPC端部加强试件峰值荷载和屈服荷载分别提高7.22%和2.72%,随着轴压比减小,HPC端部加强试件延性提升22.26%;提高腹部腔体混凝土强度等级,HPC端部加强试件的屈服荷载和峰值荷载分别提高13.01%和11.14%,延性提升16.91%。

Analytic Solution of Interaction Between Surface Waves and Floating Elastic Plates with Elastic End-Restraints

Based on the dynamic theories of water waves and Mindlin plates, the analytic solution of interaction between smface waves and two-dimensional floating elastic plates with edge-restraint is constructed by use of the Wiener-Hopf technique. Firstly, without regard for elastic edge restraint, the wave-induced responses of elastic floating plate analyzed by the present method are in good agreement with the results from literature and experimental results. Therefore, it can be shown that the present method is valid. Secondly, three end-restraint cases （i.e., the left-end elastic restraints, the both-end elastic restraints, and the right-end elastic restraints） are proposed to reduce the vibration of floating plates, in which the spring is used to connect the sea bottom and the floating plate＇ s left （ or right ） edge. The relations between the spring stiffness and the parameters of wave-induced responses of floating plates are discussed. Moreover, the effective method to reduce the vibration of floating elastic plates can be obtained through comparison.

供丝机烟丝束线性堆叠原理分析与应用

为了进一步降低ZJ112卷接机组的卷烟产品空头剔除率,通过对几种主要卷烟机型供丝装置结构、供料及成形工艺原理的研究分析,并结合废烟剔除情况,分析揭示的原理为烟丝在供丝机内从料仓到流化床的平行推进输送原理;烟丝从流化床到吸风室导轨的线性堆叠成形原理。发现了供丝机内在烟丝输送方面与空头形成相关的两个因素,设计应用的改进方案为设计安装新型螺旋绞龙底部凹口护板与延板组件;延长料仓内吸风管的长度,合理设置吸风管口在吸风腔内的位置。改进后,基本消除了回丝被重复性削刷而增加造碎劣化的问题,改善了成品烟支内的烟丝结构质量,降低了产品空头剔除率,提升了吸丝成形工艺过程控制水平。

加固后钢筋混凝土十字形柱斜向抗震性能研究

钢筋混凝土十字形柱的斜向抗震性能是影响结构安全性能的重要因素。文章设计了3种新型约束补强方式加固的钢筋混凝土十字形柱试件,在验证有限元建模方法有效性的基础上模拟了斜向低周往复加载,通过分析试件的滞回曲线、骨架曲线、承载力和延性等抗震性能指标研究了试件的斜向抗震性能,并参考相关规范得出了新型约束补强方式十字形柱的压弯承载力计算公式。结果表明:钢筋网格局部加强使试件的斜向峰值位移提高了7.4%~19.4%;柱端嵌贴碳纤维布(Carbon Fiber Reinforced Polymer,CFRP)板条会使试件峰值承载力、延性系数分别提高了约29.2%~34.2%和7.5%~22.9%;柱端嵌贴CFRP板使试件斜向峰值承载力、延性系数分别提高了约99.9%~105.5%和17.4%~24.8%。3种加固方式均可改善钢筋混凝土十字形柱的斜向抗震性能,改善程度由大到小依次为柱端嵌贴CFRP板、柱端嵌贴CFRP板条和钢筋网格局部加强。

端板攻丝高强度螺栓连接受力性能试验研究

对10.9S级M16、M20高强度螺栓和Q345B端板攻丝连接与传统高强度螺栓连接受力性能进行试验对比,研究了其在单向受拉、单向受剪以及拉-剪复合受力状态下的破坏形态、受力机理和极限承载能力。试验结果表明:单向受拉时,极限承载能力和变形与传统连接方式基本一致;单向受剪时,即使是厚径比为0.8的M20螺栓,仍可实现栓杆剪断,而端板攻丝孔内牙体无明显变形破坏且攻丝连接件形式早期滑移量明显较小;拉-剪复合受力时,随着拉剪比从0.58增大到1.73,破坏形态由剪切破坏转变为受拉破坏。因此,为确保端板攻丝牙体无明显破坏,应考虑螺栓与板厚的合理设计,建议M20螺栓在单向受拉和拉-剪复合受力时厚径比不小于0.9d,3种受力状态下高强度螺栓端板攻丝连接方式的承载力与传统连接方式基本一致。试验结果分析可为工程设计提供参考依据。

铝合金电池端板低压铸造工艺参数的设计与优化

以某新能源汽车铝合金电池端板为研究对象,基于正交试验设计以及信噪比分析法探究低压铸造过程中金属液的浇注温度、模具预热温度以及充型时间3个工艺参数对铸件成型质量的影响,以缩松缩孔体积值、凝固时间和二次枝晶间距大小为评价指标,探究出一套标准化的工艺设计参数,为新能源汽车铝合金电池端板低压铸造成型工艺研究与实际生产提供重要参考。研究结果显示:浇注温度690℃,模具预热温度330℃,充型时间8 s时铸件无缩松缩孔缺陷,二次枝晶间距最小,凝固时间最短。

一种移动式端面钻孔攻丝机的研制

自动化设备生产需要加工很多螺孔用于连接安装板,加工较长安装板的螺孔多选用立式加工中心垂直装夹,由于零件伸的太高造成装夹刚性太差;而采用卧式加工中心,设备昂贵成本太高。本文研制一款简易的端面钻孔攻丝装置,设计可移动式的工作台以降低设备占地空间,设计快速钻孔装置以提高钻孔攻丝的便捷性,增加一组工作台调节装置以扩大加工行程,改装一套攻丝系统以实现钻孔与自动攻丝功能,加装数显装置以提高孔坐标位置的精度,经过样机试制与切削实验,解决了较长安装板螺孔加工工艺问题,节约了生产成本。

铜阳极板取板机器人整机静态分析

根据铜阳极板取板的工作要求,设计了适用于取板机器人的末端执行器。运用三维软件建立了取板机器人的整机模型,利用ANSYS Workbench软件对取板机器人整机进行了静态分析,从而获得了机器人在取板位置、起始位置以及放板位置的应力和变形云图。分析结果表明,铜阳极板取板机器人在不同工况下均可以满足实际生产需求。

端盘型螺杆泵测试装置的分析和优化设计

通过对端盘型螺杆泵在产品测试时效率较低的原因进行分析,提出用于端盘型螺杆泵产品测试装置的优化方案,将端盘型螺杆泵进、出口方向组合方式进行固定,在测试时固定端盘型螺杆泵进口的方向,通过在端盘型螺杆泵出口位置设置旋转接头以及平面支承等相关零部件,使测试装置能够满足端盘型螺杆泵多个进、出口方向组合方式的测试要求。通过优化方案,可对端盘型螺杆泵的测试过程进行简化,这样可以解决在端盘型螺杆泵产品测试中测试效率不高、测试调整过程繁琐等问题,实现通过一套测试装置能够快速满足不同规格端盘型螺杆泵各种进、出口方向组合方式的测试工作,提高测试效率,节约测试成本,更好地满足端盘型螺杆泵的高效产出。

含黄铁矿填料的高速铁路路基上拱特性与机理

黄铁矿氧化膨胀对建筑物、铁路、公路等结构的影响较大,易引发结构物上拱。通过现场勘察、矿物成分分析和变形监测,系统研究含黄铁矿填料路基上拱病害特征,探究摩擦板及端刺结构型式、路基填料高度对路基上拱变形的影响,分析黄铁矿氧化膨胀反应机理和膨胀特性,以明确路基上拱原因。结果表明:所有上拱区段路基填料均检测出含有少量黄铁矿和石膏;上拱变形主要产生在路基高度范围内,线路开通后路基以0.13~0.46 mm·m^(-1)的速率持续上拱;半填半挖区段轨道结构的上拱量沿路基横向随填方高度的降低呈递减关系;路桥过渡段范围轨道垂向变形特征与摩擦板及端刺结构型式密切相关,摩擦板及端刺结构对路基上拱变形存在抑制作用;黄铁矿氧化是一个长久且持续过程,其生成硫酸盐引发的一系列化学反应所伴随的体积膨胀是造成路基上拱的主要原因;为彻底消除该隐患,应对含黄铁矿填料采取暗挖置换措施。

钢框架梁柱外伸式端板连接的非线性有限元模拟

钢框架梁柱外伸式端板连接作为一种典型的半刚性连接方式,其受力性能较为复杂。为全面了解该连接方式下的受力特性,采用ANSYS Workbench软件建立有限元分析模型,在考虑材料非线性、几何非线性、状态(接触)非线性的情况下,分析连接节点在高强度螺栓预紧力及竖向位移荷载作用下的受力性能。研究结果表明:1)在预紧力作用下,螺栓与端板的接触压力集中分布在螺栓孔的周边,分布面积约为螺栓杆截面面积的10倍;2)设置柱腹板加劲肋及端板加劲肋是外伸式端板连接节点必不可少的构造措施;3)受拉区高强度螺栓受到较大的拉力和剪力,受压区螺栓在弹塑性阶段也会承受较大的剪力。本文成果可为钢框架梁柱外伸式端板连接的分析与设计提供一定的借鉴与参考。

基于三参数模型的方钢管柱-H型梁单向螺栓端板连接节点承载力研究

单向螺栓可较好地解决封闭截面内使用普通螺栓带来的施工不便和焊缝连接易发生脆性断裂等问题。为探索方钢管柱与H型梁单向螺栓端板连接节点的承载性能和影响因素,分别对梁柱平齐式端板连接节点和梁柱外伸式端板连接节点进行静力加载试验。试验通过校准有限元模型,发现两组数据吻合度较高,对此通过改变方钢管柱、H型梁和端板的截面参数与单向螺栓的直径建立了有限元模型进行承载力分析。研究结果表明:梁高度、柱壁厚度和螺栓直径对梁柱平齐式端板连接节点和梁柱外伸式端板连接节点的初始刚度和极限弯矩都有较大影响;梁柱外伸式端板连接节点的初始刚度和极限弯矩还受端板的宽度和厚度的影响。最后基于三参数模型拟合出初始刚度、极限弯矩和形状系数的近似公式,为此类节点在工程中的应用提供了参考。

新型高性能大产能电解水制氢装置的研究与应用

氢气来源广泛、热值高、清洁无碳,在未来很长一段时间内氢能将是我国重要的新能源。而在电解制氢领域中,碱性电解水制氢技术发展最为成熟,并且将会有着长足的发展空间。主要从电解槽关键材料的研究、极板关键零部件制备技术、轻量化端压板设计关键技术、AWE热管理系统设计关键技术等方面介绍了新型电解水制氢装置关键技术研究,并对市场发展前景、应用案例进行了分析展望。