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某型航空发动机压气机叶片振动疲劳寿命研究 总被引:6,自引:0,他引:6
以某型航空发动机压气机叶片为研究对象,在室温条件下进行了一阶弯曲振动疲劳试验,确定了叶片1×107循环基数下的振动疲劳极限.疲劳寿命分析表明在低振动应力下,Basquin方程可以很好地预测叶片的振动疲劳寿命.但在较高振动应力下,Basquin方程预测叶片的疲劳寿命偏于危险,原因在于Basquin方程不能反映塑性滑移对疲劳损伤的影响.为解决这一问题,引入了一个新的应变比因子对Basquin方程进行了修正.对于较高振动应力770MPa和740MPa下叶片的振动疲劳寿命而言,修正后的方程寿命预测误差分别为78.7%和38.5%.与原始Basquin方程相比,修正后的方程寿命预测精度分别提高了66.0%和19.2%. 相似文献
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提出了基于Lyapunov指数谱和Lyapunov指数谱熵的航空发动机状态识别和故障诊断新方法。基于实测的某型航空发动机振动时间序列求解了系统不同工作状态和故障状态的Lya-punov指数谱;基于Lyapunov指数谱,对该型航空发动机进行了状态识别和故障诊断;为给出对Lyapunov指数谱及其对状态识别和故障诊断的整体表述,定义了Lyapunov指数谱熵,并基于该谱熵对该型航空发动机进行了状态识别和故障诊断。研究结果表明该型航空发动机振动时间序列在不同状态下具有不同的Lyapunov指数谱及其谱熵,即可以Lyapunov指数谱及其谱熵作为识别其状态的特征量,为航空发动机的故障诊断和状态监控提供了新的可靠的方法。 相似文献
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本文中以476728航空发动机主轴球轴承高速重载典型工况为算例,提出一种将轴承动力学分析和热弹流润滑分析相集成的数值算法,打破传统分析中二者在各自领域独立进行的局限性,提高了轴承数值计算的精确度.对比了传统拟动力学分析、集成分析和实验实测的最小膜厚,结果表明:集成分析结果与试验获得数据更为一致,证明本文的算法可行,能够更为准确地判断航空发动机主轴球轴承的润滑状态.探讨了航空发动机主轴球轴承结构参数曲率系数、初始接触角和滚动体数目对轴承接触应力、相对滑动速度、弹流润滑膜压力、膜厚和温度性能的影响,为航空发动机主轴球轴承的结构设计及优化提供重要理论依据. 相似文献
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Abstract According to the three key elements in blade design process, i.e., aerodynamic design, structure design, and load prediction, the independent research and development (R&D) progress of blade design is summarized and analyzed. The calculational fluid dynamics (CFD) method, the vortex method, and the blade element momentum method (BEM) are described. Based on the widely used BEM method, the solutions for the blade design in low-speed wind area are obtained. A brief overview of the traditional design and analysis methods based on beam models is given. The defects of these methods used for simulating the structure of large-scale composite blade are analyzed. The application progress of the finite element method (FEM) used in the blade structure analysis is shown. The effects of load prediction on the blades and entire wind turbine are introduced. The progress in load forecasting is described. With the analysis of the relationship among these three key elements, it is concluded that developing a blade optimization design system with coordinated aerodynamics, structure, and load will truly meet the requirement of high efficiency and low cost. The main directions for further study are pointed out, e.g., high efficiency and low load airfoils, structural nonlinear finite element analysis, aerodynamic structure coupling research, and establishing different design standards. The aim is to establish a blade R&D system suitable for the conditions of wind resources in China and promote the development of wind power in the country. 相似文献
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Deshun LI Rennian LI YinranLI Xiuyong WANG Liejiang WEI Yan QIANG Zhiqiang LIU 《应用数学和力学(英文版)》2016,37(Z1):31-42
Field experiments are performed on a two-bladed 33 kW horizontal-axis wind turbine (HAWT). The pressures are measured with 191 pressure sensors positioned around the surfaces of seven spanwise section airfoils on one of the two blades. Three-dimensional (3D) and two-dimensional (2D) numerical simulations are performed, respectively, on the rotor and the seven airfoils of the blade. The results are compared with the experimental results of the pressure distribution on the seven airfoils and the lift coefficients. The 3D rotational effect on the blade aerodynamic characteristics is then studied with a numerical approach. Finally, some conclusions are drawn as follows. From the tip to the root of the blade, the experimental differential pressure of the blade section airfoil increases at first and then decreases gradually. The calculated 3D result of the pressure distribution on the blade surface is closer to that of the experiment than the 2D result. The 3D rotational effect has a significant impact on the blade surface flow and the aerodynamic load, leading to an increase of the differential pressure on the airfoils and their lift coefficient than that with the 2D one because of the stall delay. The influence of the 3D rotational effect on the wind turbine blade especially takes place on the sections with flow separation. 相似文献
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为寻求在设计阶段能较准确地预测重载货车车体焊缝的疲劳寿命评估方法,基于各种标准提供的分析方法对转炉616装甲钢T型焊接接头进行疲劳评估,通过与试验的对比表明,美国ASME标准中的等效结构应力法更能准确预测焊缝的疲劳寿命。为提高某重载运煤敞车车体焊缝的疲劳寿命,建立了包括焊缝在内的敞车车体有限元模型,基于等效结构应力法和AAR标准中的载荷谱,预测了车体关键焊缝的疲劳寿命,其薄弱部位与车体实际发生疲劳裂纹部位基本吻合,依据焊缝的结构应力分布规律的特点,提出的枕梁改进结构可使车体关键焊缝疲劳寿命提高1.7倍。 相似文献
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为研究扁平钢箱梁温度疲劳应力谱,以南溪长江大桥悬索桥主梁为研究对象,基于温度传感器长期实测数据,筛选实测数据的日温度极值,运用广义极值模型描述季节极值概率分布并采用极值外推方法得到设计基准期极值模型。引入拉丁超立方抽样(LHS)法对极值模型进行抽样,得到日温度极值样本。结合日温度极值样本和正弦函数模型,构建服役期内关注点的温度时程曲线。基于有限元ANSYS软件平台,分析不同温度梯度下关注点的应力效应,回归温度梯度与疲劳应力的线性关系式,依据温度梯度时程曲线与线性关系式模型,采用雨流计数法得到钢箱梁温度梯度疲劳应力谱。研究表明,模拟抽样生成的温度样本数据符合温度场的季节变化特征,样本概率模型与实测数据概率模型相对吻合。关注点温度梯度疲劳应力谱能够为扁平钢箱梁疲劳寿命设计提供参考。 相似文献