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为分析输电塔—线体系的风效应,设计并制作了输电塔—线体系完全气弹模型,通过风洞试验测试了不同风速和风向角下单塔沿高位移响应、导线线端张力作用下的绝缘子动应变,导线1/4、1/2和3/4跨位移响应以及挂线后输电塔沿高位移响应。结果表明,输电塔挂线与不挂线位移响应随风速递增,且塔顶位移变化显著;强风作用下导线发生明显的风偏振动;挂线后输电塔线体系振动呈非线性耦合特性。重现了输电塔在极限风荷载作用下的风毁现象,与实际破坏模式相符。可见通过对输电塔进行局部优化,可在增加少量构件的情况下,使倒塔极限风荷载得以显著提高。 相似文献
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基于桩静荷载Q-s曲线特点,引入MMF生长曲线模型拟合Q-s曲线预测极限承载力,采用Origin软件求解,并对3根试桩的实测数据静荷载Q-s曲线进行了拟合和承载力预测.结果表明,利用Origin软件得到的拟合方程式能预测桩的极限承载力,且MMF模型的Q-s曲线拟合精度高、拟合效果明显优于双曲线模型. 相似文献
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为了研究500/220 k V混压多回窄基钢管塔塔脚节点的受力性能及承载力情况,利用有限元软件ANSYS,对该塔进行建模及有限元分析。研究其在轴力和弯矩共同作用下塔脚节点应力分布、塑性发展、节点破坏模式及极限承载力情况,以期准确把握该类钢管塔塔脚节点的力学行为,为工程设计和后续的研究工作提供相关的比较数据。研究表明,塔脚节点最终破坏形式是肋板以上主管管壁的鼓曲破坏,设计荷载作用下塔脚节点未发生破坏。同时,通过承载能力极限状态的分析,对设计中次应力需要考虑的大小做出了量化,提出了考虑次应力影响的输电钢管塔主材设计方法,使实际设计更为经济化。 相似文献
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随着电网的智能化发展,对输电铁塔不同工况下的承载力性能要求越来越高,煤矿采空区输电线路铁塔基础变形后及扶正过程中的要求更不能忽视。建立了采空区输电线铁塔的ANSYS有限元模型,设计了不同组合荷载工况承载力性能评估的方法,对基础变形后及扶正过程中铁塔的承载力性能进行了分析评估。基于500 k V徐辽线53号变形铁塔说明了该方法,对53号塔基础沉降、大板基础倾斜及设置拉线后3种情况进行了承载力性能分析评估,涉及到不同风速、风向的风力荷载及覆冰荷载的多种组合工况。结果表明:该性能评估方法在采空区输电线铁塔主材应力超限、主材轴力变化及沉降量临界值的评估方面有一定优势,这对采空区输电线路铁塔的承载力及稳定性设计有一定参考价值。 相似文献
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Long‐term contact fatigue analysis of a planetary bearing in a land‐based wind turbine drivetrain 下载免费PDF全文
This paper presents an approach for performing a long‐term fatigue analysis of rolling element bearings in wind turbine gearboxes. Multilevel integrated analyses were performed using the aeroservoelastic code HAWC2, the multibody dynamics code SIMPACK, the three‐dimensional finite element code Calyx and a simplified lifetime prediction model for rolling contact fatigue. The National Renewable Energy Laboratory's 750 kW wind turbine and its planetary bearing were studied. Design load cases, including normal production, parked and transient load cases, were considered. To obtain the internal bearing load distribution, an advanced approach combining a finite element/contact mechanics model and a response surface model were used. In addition, a traditional approach, the Harris model, was also applied for comparison. The long‐term probability distribution of the bearing raceway contact pressure range was then obtained using Weibull and generalized Gamma distribution functions. Finally, we estimated the fatigue life of the bearing, discussed the differences of the methods used to obtain the bearing internal loads and analyzed the effects of the environmental conditions and load cases on the results. The Harris model may underestimate the inner raceway life by 55.7%, which can cause large load fluctuations along the raceways. The bearing fatigue life is very sensitive to the wind distribution and less affected by the transient and parked load cases. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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Shoujun Chen Qiang Li Yi Zhang Qi An 《International Journal of Pressure Vessels and Piping》2011,88(2-3):88-93
Based on elastic mechanics and by use of thick cylinder theory, this paper presents a finite element analysis model with interference fit and axial load on P-110S conic threaded connections and the tooth load distributions on contact threaded surfaces were investigated. A 2D finite element model with elastic-plastic axisymmetric contact threaded surfaces was established and the tooth load distributions on its thread teeth were analyzed under different interference fit and axial load. Results for the loads on every engaged tooth are obtained. These indicate that the load distribution on the engaged teeth is not uniform, with the maximum tooth load concentrated on the first three pairs or the farthest two pairs of engaged teeth from the pin end and the middle teeth only bear a very small load. Such results are identical to the practical situation and indicate that the finite element model proposed in this paper is reasonable. 相似文献
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建立一种针对表面硬化滚道三排圆柱滚子风电主轴轴承的疲劳寿命分析方法。首先,在卡迪尔坐标系中建立三排圆柱滚子风电主轴轴承的5自由度力学模型,分析计算在外部5个方向载荷联合作用下轴承的内部滚子载荷分布;然后,建立圆柱滚子与表面硬化滚道之间的弹塑性接触有限元模型,计算得到滚子接触载荷作用下滚道次表面的脉动应力分布;最后,根据Goodman方程将滚道脉动应力幅值转化为交变应力幅值,运用Basquin应力-寿命理论计算得到风电主轴轴承的疲劳寿命。结果表明,轴承的下风向外圈滚道承受来自风轮的推力载荷,其疲劳寿命最短;径向外圈滚道承受风轮的重力载荷,其疲劳寿命最长。轴承的疲劳寿命取决于下风向滚道。 相似文献
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发动机主轴承座结构强度分析研究 总被引:12,自引:0,他引:12
建立了包括缸体、框架、轴瓦、曲轴及连接螺栓的发动机主轴承座网格模型,通过指定不同的接触区域、接触条件、载荷、约束边界条件及多点约束,分别建立了螺栓预紧、轴瓦过盈、曲轴动压力及热负荷四种工况主轴承座强度分析有限元模型。采用二阶修正单元并通过接触主从面上单元的对应性来保证计算精度和收敛性,采用小滑移接触算法计算出各工况下主轴承座的应力和变形情况,根据计算结果,对主轴承座的强度、变形、滑移表面的滑动以及轴瓦背面的压力分布进行了评价,对主轴承座结构提出了改进意见,改进方案满足结构设计要求。 相似文献
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Abstract Contact stresses and residual bearing strength of pin-loaded composite laminates at different temperatures are investigated. An incremental finite element code, based on the updated Lagrangian approach, was developed for determining the contact stresses near a pin-loaded hole in composite laminates under combined thermal and mechanical loadings. Based on the progressive damage model, the quadratic strength theory combined with a proposed failure simulation are adopted for failure predictions. In the stress and strength analyses, mechanical properties of the laminates are assumed to be temperature dependent. Numerical results include the distributions of initial (thermal) as well as total contact stress around the pin-loaded hole, residual bearing strength, and failure mode for a single-fastener clearance-fit joint with an elastic pin. The bearing strain model test has been performed at elevated temperature for the verification of present calculations. 相似文献
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针对集中参数法难以考虑齿圈柔性而有限元法计算量大的问题,以风电行星轮系为研究对象在集中参数/有限元混合法基础上提出一种揭示内啮合齿轮副延长啮合现象的分析方法。首先采用集中参数法建立风电行星轮系的动力学模型,并求解获得动态啮合力;随后,运用有限元法建立行星轮系内啮合齿轮副的有限元模型,并开展静态接触分析从而获得内啮合齿轮副各啮合位置发生多齿啮合时的变形阈值;最后,将集中参数模型获得的动态啮合力施加在内齿圈有限元模型上计算出内齿圈的动态响应,并结合发生多齿啮合时的变形阈值,从而揭示在不同负载和支撑数量下内齿圈上多齿啮合的分布区域,获得接触应力和齿根应力,分析啮合齿对数量改变前后对应力的影响。结果表明:考虑齿轮柔性后,内啮合齿轮副会出现除理论啮合齿对外其他齿对相接触的现象;随着负载扭矩的增大,内齿圈上三齿啮合首先发生在支撑两侧,随后三齿啮合发生区域不断增加;当行星轮与内齿圈间的啮合由理论两齿啮合变为三齿啮合时,其齿面接触应力和齿根应力小于其在相同时刻只计入两齿啮合时的应力值。 相似文献
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为分析加载方向对加翼桩极限横向承载力的影响,采用ABAQUS有限元软件建立数值分析模型,定量分析软粘土地基中单桩和三种典型加载方向下加翼桩的受力变形特性和极限横向承载力。依据数值分析结果,采用数值逼近方法建立了加载方向影响系数k3的经验公式,以反映加翼桩极限横向承载力与加载方向的关系,对现有计算方法进行了补充,并对其适用性进行了分析。结果表明,加翼桩横向位移和内力的分布与单桩的规律相似,桩身和翼板连接处易出现应力集中现象,极限横向承载力较单桩的显著提高。加载方向对加翼桩极限横向承载力影响较大,当横向荷载与前翼板夹角增大,极限横向承载力显著降低。经验公式计算精度良好,可较好地反映加翼桩极限横向承载力与加载方向的关系,可为工程设计提供参考。 相似文献
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G. Mathan N. Siva Prasad 《International Journal of Pressure Vessels and Piping》2011,88(11-12):495-500
The behavior of a gasketed flange joint under bending loads has been studied by three dimensional finite element analysis (FEA) and experiments. The in-plane and bending stiffness of spiral wound gaskets are considered using anisotropic Hill plasticity material model. The variation in bolt axial force of joints under bending load predicted by the finite element analysis compares well with the experimental results. The contact stress distribution obtained have significant variation in the pattern from the previous material models and consistent with the results of Bouzid [1] regarding flange rotation. 相似文献
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枞树型叶根广泛应用于燃气轮机和大功率蒸汽轮机叶片,其可靠性严重影响着叶片的安全运行.采用三维热弹性有限元分析技术建立了仅考虑离心力载荷及综合考虑离心力和温度载荷的数值模型,对4种不同的叶根轮缘接触面制造偏差状况下叶根应力进行了详细分析,发现常温下设计良好的枞树型叶根轮缘,在高温下由于热胀导致的变形,将使叶根承载分布不均,从而产生很大的应力,并且应力状况也随着制造偏差而不同.所以在设计高温级叶片枞树型叶根型线时,需要综合考虑叶根的制造偏差以及工作状态下的承载情况进行安全性校核. 相似文献