共查询到18条相似文献,搜索用时 62 毫秒
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大型水轮发电机组轴系临界转速模拟试验研究 总被引:3,自引:2,他引:1
针对大型水轮发电机组轴系临界转速难以实际测定的现实问题,从理论分析的角度出发,抓住水力机组轴系结构的基本特点,提出采用较为简单的模拟结构,试验研究水力机组轴系固有频率及其振型特征。初步研究结果已在理论分析和实际机组中得到验证。 相似文献
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针对大型水轮发电机组轴系临界转速难以实际测定的现实问题,从理论分析的角度出发,抓住水力机组轴系结构的基本特点,提出采用较为简单的模拟结构,试验研究水力机组轴系固有频率及其振型特征。初步研究结果已有理论和实际机组中得到验证。 相似文献
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针对瓦楞辊工作过程中产生的振动与噪声等现象,高速运行下在机架上对瓦楞辊传动系统进行了现场振动测试,使用随机子空间法从测试数据中识别了结构的前十阶模态频率及相应的振型和阻尼比,并与有限元分析结果进行比较。结果表明,通过机架的振动情况可较为准确地提取出上、下瓦楞辊的各阶频率;有限元模型能够准确地反映瓦楞辊的动态特性,可以为瓦楞辊结构的故障诊断及变形预测提供参考。 相似文献
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Ta Na State Key Laboratory of Vibration Shock Noise Shanghai Jiaotong Univernty Shanghai Chana Qiu Jiajun Cai Ganhua School of Mechanical Engineering Tianjin University Tianjin China 《机械工程学报(英文版)》2005,18(2):302-306
Zero mode natural frequency (ZMNF) is found during experiments. The ZMNF and vibrations resulted by it are studied. First, calculating method of the ZMNF excited by electromagnetic in vibrational system of coupled mechanics and electrics are given from the view of magnetic energy. Laws that the ZMNF vanes with active power and exciting current are obtained and are verified by experiments. Then, coupled lateral and torsional vibration of rotor shaft system is studied by considering rest eccentricity, rotating eccentricity and swing eccentricity. Using Largrange-Maxwell equation when three phases are asymmetric derives differential equation of the coupled vibration. With energy method of nonlinear vibration, amplitude-frequency characteristics of resonance are studied when rotating speed of rotor equals to ZMNF. The results show that ZMNF will occur in turbine gen erators by the action of electromagnetic Because ZMNF varies with electromagnetic parameters, resonance can occur when exciting frequency of the 相似文献
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为能够对大型复杂旋转机械转轴动态载荷特性进行在线监测,给出一个表征转轴动载特性的参量——动载波动系数KID。应用动力学理论推导出动载波动系数KID测量模型的数学表达式,该式表明测得转轴转速波动值即可求得KID值。基于激光多普勒技术,提出一种直接提取动载波动系数KID的激光测量方法。通过构造光学测试系统测量相邻时刻转轴轴段两端面的瞬态转速,得到轴段转速波动值及两端面相对转速波动值,代入KID测量模型,能够直接得到动载波动系数KID值,从而实现对转轴扭振强度的实时监测。通过试验验证了该方法的可行性,结果表明,动载波动系数KID较好地反映了转轴的动态载荷波动特性,能为工程中大型复杂旋转机械转轴动态扭振监测提供新方法。 相似文献
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尽管计算机和有限元软件的发展已使复杂结构固有频率的计算变得很容易,但在某些场合仍然使用简便方法来估计振动系统的基频,文中基于瑞雷法,导出计算多自由度系统振动基频的新算法,并就两个算例与文献所提供的其他方法进行比较,理论分析和算例比较表明。(1)新算法计算量约是瑞雷法的两倍,但无须假设基频振型,即可得到精确的基频。(2)适用于柔度矩阵已知的情形。 相似文献
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Aiming at providing with high-load capability in active vibration control of large-scale rotor system, a new type of active actuator to simultaneously reduce the dangers of low frequency flexural and torsional vibrations is designed. The actuator employs electro-hydraulic system and can provide a high and circumferential load. To initialize new research, the characteristics of various kinds of active actuators to control rotor shaft vibration are briefly introduced. The purpose of this paper is to introduce the preliminary results via presenting the structure, functions and operating principles, in particular, the working process of the electro-hydraulic system of the new actuator which includes a set of high speed electromagnetic valves and a series of sloping cone-shaped openings, and presenting the transmission relationships among the control parameters from control signals into the valves to active load onto shaft. The course of the work is dynamic, and a series of spatial forces and moments are put on the shaft to get an external resultant force to reduce excitations that induce vibration of shafts. By checking states of vibration, the actuator can control the impulse width and the interval of injection time for applying different control force to a vibration shaft in two circumference directions through the regulating action of a set of combination directional control valves. The results from simulating analysis and experiment show evidence of that this design can satisfy the case of active process of decreasing of flexural and torsional vibrations. 相似文献
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弯扭组合轴表面裂纹应力强度因子修正系数的光弹性确定 总被引:5,自引:0,他引:5
评价了将轴表面半椭圆裂纹简化为有限边界平板和单边裂纹问题和半无限体表面穿透直线裂纹问题来处理的局限性。通过三维光弹实验成功地测定了轴表面半椭圆裂纹前缘各点的应力强度因子SIF,并根据几组弹数据回归出轴表面对SIF的影响修正系数MY与裂纹相对深度α/F之间的关系曲线。 相似文献
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对传递矩阵法识别机床主轴系统支承动态参数的原理和应用进行了研究,并在此方法中引入了“拟合圆法”,以提高识别精度,用在此基础编制的计算机程序,在主轴系统实际安装条件下,根据各测点的位移异纳试验数据,对机床主轴系统支承动态参数进行了识别计算。 相似文献