摘要
从结构的数字化模型频响函数出发,利用最小二乘复频域法识别模态参数,进一步用获取的模态参数修正集中质量法推导出的物理参数,从而建立符合结构动力特性的数学模型。首先通过固支梁模型算例验证该方法的可行性;然后对600 MW大型汽轮发电机端部绕组的精细化有限元模型进行模态分析,并与实测结果进行对比,验证了该模型的合理性;此后,基于该有限元模型获取的频响函数和模态参数,识别出端部绕组的物理参数并建立其数学模型。结果表明:在75~115 Hz频率段中,最小二乘复频域法识别出的端部绕组模态与有限元结果对比表明,固有频率和阻尼比的最大误差出现在第一阶模态中,分别为0.27%和0.50%,模态振型接近;通过数学模型和有限元模型计算的端部绕组固有频率最大误差为0.27%,模态振型一致;数学模型计算的频响函数与有限元结果对比表明,测点的频响函数最高匹配度可达95%,多数测点的频响函数匹配度超过85%。该方法可为大型汽轮发电机定子端部绕组动力学的准确建模提供依据。
Here,starting from frequency response functions(FRFs)of structure digitization model,using the least squares complex frequency domain method to identify modal parameters,further using obtained modal parameters to modify physical parameters derived with the lumped mass method,a mathematical model conforming to a structure’s dynamic characteristics was established.Firstly,the feasibility of this method was verified with a clamped-clamped beam model example.Then,modal analysis was conducted for the refined finite element model of stator end winding of a 600 MW large steam turbine generator,and the rationality of the model was verified by comparing its modal analysis results with actual measured results.Afterwards,based on FRF and modal parameters obtained with the finite element model,physical parameters of the stator end winding were identified and its mathematical model was established.The results showed that within the frequency range of 75-115 Hz,after comparing stator end winding modes identified with the least squares complex frequency domain method and those with the finite element model,maximum errors of natural frequencies and damping ratios occur in the first order mode,they are 0.27%and 0.50%,respectively,and the corresponding modal shapes are close to each other;the maximum error between natural frequencies of stator end winding calculated with the mathematical model and with the finite element model is 0.27%,and the corresponding modal shapes are consistent;after comparing FRFs calculated with the mathematical model and with the finite element model,the highest matching degree of FRFs at measured points can reach 95%,the matching degree of FRFs at most measured points can exceed 85%;the established method can provide a basis for accurate establishment of stator end winding dynamic model of large turbogenerators.
作者
赵洋
刘晋珲
肖洋
邓聪颖
马莹
ZHAO Yang;LIU Jinhui;XIAO Yang;DENG Congying;MA Ying(School of Advanced Manufacturing Engineering,Chongqing University of Posts and Telecommunications,Chongqing 400065,China;Institute for Advanced Sciences,Chongqing University of Posts and Telecommunications,Chongqing 400065,China;State Key Lab for Strength and Vibration of Mechanical Structures,Xi’an Jiaotong University,Xi’an 710049,China)
出处
《振动与冲击》
EI
CSCD
北大核心
2024年第5期202-213,共12页
Journal of Vibration and Shock
基金
国家自然科学基金(51807019)
机械结构强度与振动国家重点实验室开放基金(SV2020-KF-15)。
关键词
定子端部绕组
模态参数
物理参数
数学模型
频响函数(FRF)
stator end winding
modal parameter
physical parameter
mathematical model
frequency response function(FRF)
