转子系统不平衡响应计算的Riccati传递矩阵法

不平衡响应分析是转子系统动力特性计算与设计中的重要环节,传递矩阵法是计算转子系统不平衡响应的方法之一.介绍了计算转子系统振动不平衡响应的Riccati传递矩阵法,并用M ATLAB软件编写程序对其进行数值计算,得到单盘转子上的圆盘有偏心时系统的不平衡响应曲线图.     

各向异性支承的分布质量转子系统的稳定性分析

某燃气轮机高压涡轮是一个带有24个轮盘的分布质量转子系统,具有不对称的支承特征.文中首先采用集中质量和无质量弹性轴段进行建模,根据设计要求引入两个各向异性弹性支承,构建具有25个轴段的集总质量转子系统动力学模型.给出了用Riccati传递矩阵法计算该转子系统复频率的算法,计算得到各阶临界转速.利用对数减幅率判据对转子系统的稳定性进行判定,讨论了转速等因素对各阶模态下转子系统稳定性的影响.所得结果为该复杂转子系统的动力学设计提供了依据.     

异常情况下转子系统的不平衡响应特性

用Riccati传递矩阵法计算分析了支撑系统异常情况下转子的不平衡响应特性。分析结果表明，支撑刚度不对称情况下，在转子上加对称不平衡量，不仅激发一阶分量，同时还激发出明显的二阶分量，同样，加反对称不平衡量，不仅激发二阶分量，同时还能激发出明显的一阶分量，转子不平衡响应特性发生了很大变化。该结论对于指导机组动平衡具有非常重要的工程应用价值。     

复杂非线性转子-轴承系统的偏置协调响应分析

提出了一个利用等效线性化技术将非线性元件—挤压油膜阻尼器-换为具有等效参数的线性元件,然后用R iccati传递矩阵法分析等效系统偏置协调响应的迭代法。本方法简便易于掌握,稳定性好,计算效率高,比模态综合法大大提高而且每个非线性元件的线性化可独立地进行。因此,对含有多个非线性元件的复杂多转子系统,用本法分析其偏置协调响应特别适合。     

用粘弹性轴承支撑减少轴承转子系统的不平衡响应

讨论了聚合或粘弹性轴承支撑对轴承转子系统不平衡响应的影响。在详细分析的基础上,设计了计算粘弹性支撑参数的程序。计算结果表明：合理地选择粘弹性支撑参数和材料,可以在较宽频域内降低轴承转子系统的不平衡响应。     

大型屏蔽电机泵转子系统的建模及临界转速计算

建立了大型屏蔽电机泵转子系统的集总参数模型,并采用Riccati传递矩阵法对转子系统的临界转速及振型进行了计算。计算结果表明:(1)采用Riccati传递矩阵法编制的转子系统临界转速求解程序计算稳定,计算精度足够高;(2)大型屏蔽电机泵转子系统的临界转速为设计超速的1.2倍,能够有效避开工作转速,设计裕量足够;(3)在正常工作下,转子系统上、下飞轮处为振动敏感部位,应重点监测,以免和承压壳体发生碰磨。     

锥齿轮传动转子系统纵弯扭耦合振动的不平衡响应

研究了在外载荷作用下锥齿轮传动转子系统纵弯扭耦合振动的不平衡响应.建立了锥齿轮传动转子系统纵弯扭耦合振动的力学模型,通过作用在系统上不平衡量和不同外载荷,分析了由于纵弯扭耦合效应对不同转子之间不平衡响应的影响;讨论了外载荷的变化对不平衡响应的影响.结果表明外载荷会引起轴承特性的变化,从而影响系统的不平衡响应.     

大型离心压缩机转子系统不平衡响应分析

以某大型离心压缩机转子系统为研究对象,考虑膜片联轴器和5瓦可倾瓦轴承的影响,首先建立转子-轴承系统的有限元模型;然后按照相关标准进行不平衡响应计算,分析了各种轴承参数,如长径比、间隙比以及润滑油型号对轴颈振幅的影响;最后将所得到的结果与工厂试车数据进行了对比分析,研究结果可为压缩机转子系统轴承参数选择提供理论参考.     

转子不平衡故障模拟及其不平衡响应测量分析平台研究

针对难以通过在现场大型旋转机械上预设不平衡,研究不平衡量辨识方法问题,研发了转子不平衡故障模拟试验台及转子不平衡响应测量分析系统。研制了由无刷直流电动机及其驱动器、滚动轴承、转轴、偏心转盘等组成的轴承-转子系统,通过改变配重在转盘上的安装位置模拟了转子不平衡故障;设计了由电涡流传感器、光电传感器、数据采集卡等组成的测量与分析系统硬件,利用LabVIEW开发了基于截取脉冲分析法的转子不平衡响应测量与分析系统专用软件,实现了转子键相脉冲和不平衡响应信号的采集与存储以及不平衡响应幅值和相位的分析;考虑测量噪声,设计了基于LabVIEW的仿真实验。研究结果表明:截取分析的周期不同,识别误差也不同,但幅值相对误差最大为2.023 9%,相位绝对误差最大为2.441 9°。     

矿用通风机转子系统振动特性研究

通过建立矿用通风机转子系统的有限元等效简化模型和进行转子系统的振动模态分析,以及利用MATLAB基于Riccati传递矩阵算法求解该转子系统的临界转速和固有频率,可以验证之前有限元求解方法的准确性.该分析方法可为通风机转子系统的前期设计提供参考,对提高其整体性能具有重要工程应用价值.     

薄膜蒸发器转子系统固有频率及稳态不平衡响应分析

薄膜蒸发器转子系统中的不平衡力易导致转子振幅加大,从而加剧刮板磨损,导致刮板失效.采用VB对ANSYS进行二次开发,对薄膜蒸发器转子系统进行模态分析,并对转子某些位置上的不平衡量进行了稳态不平衡响应分析,初步实现了薄膜蒸发器转子动力学分析,为薄膜蒸发器设计及安全运行提供依据.     

支座松动转子系统的振动特性分析

针对一端轴承支座与基础之间出现松动的情况，建立了转子-轴承系统的数学模型，利用数值积分等方法对该系统进行了数值模拟。模拟结果表明，系统运动具有多种形式1支座发生松动振动时很容易引起系统的1／3厦其倍数次的振动频谱分量，且频谱成分多以低频为主，伴随幅值较小的高频成分。     

Transfer matrix for rotor coupler with parallel misalignment

A transfer matrix for shafts coupler with parallel misalignment (offset) was derived. The responses of a rotor system composed of flexible shafts, unbalanced disks, elastic supports and shafts coupler with misalignment were then investigated. Through the derivation, the boundary shears induced by a rotating shaft were first discovered to be coupled in two perpendicular directions. These coupling shears might reduce the first critical speed up to 50% in the free-free case. The studies showed that the shafts coupler altered the rotor’s critical speeds and the misalignment played as an external load resulting through the whole driven shaft. The combined effects of disk unbalance and shaft misalignment showed that the misalignment predominated the response in most of the rotation speeds, but the unbalance could become significant at high speed. The whirling orbits before and after the misalignment were illustrated as well, and numerical results showed that the two ends of the misalignment whirled asynchronously as the rotation fell into some regions. This paper was recommended for publication in revised form by Associate Editor Seong-Wook Hong Shyh-Chin Huang received a M.S. degree in Mechanical Engineering from University of Iowa in 1984, and a Ph.D. degree in Mechanical Engineering from Purdue University in 1987. Dr. Huang is currently a distinguished professor and researcher at National Taiwan University of Science and Technology. His research interests are in the area of vibration controls, smart materials and electric shunt damping design. Dr. Huang is currently an editor of Research Letters in Materials Science. Chao-Yang Tsai received a M.S. degree in Mechanical Engineering from National Taiwan University of Science and Technology in 1997.Now he is studying at the same department for the Doctor Program. He is currently an instructor at the Army Academy R.O.C, teaching basic technological science including Engineering Mechanics, Mechanics Materials and so on.     

The vibration of a multi-crack rotor

In this paper a mode of free vibrational analysis of multi-cracked rotor is presented. The cracks are assumed to be in the first mode of fracture, i.e. the opening mode. Based on the Timoshenko beam theory, the frequency equation can be constructed by assembling the transfer matrix of each segment of the multi-step and multi-cracked rotor, and then solve the frequencies as well as the corresponding mode shapes of the cracked rotor. The effects of both relative distances along axis and/or orientations of cracks are considered in free vibration analysis. An algorithm and numerical examples are included.     

动力响应问题的摄动Riccati传递矩阵方法

基于Riccati传递矩阵法,给出了一维不确定参数结构系统动力学响应问题的二阶摄动计算方法。该方法在用于一维结构系统动力响应问题的摄动分析时,不需要按振型展开,避免了基于有限元的矩阵摄动方法所带来的模态截断误差问题,提高了分析结果的精度。以多跨转子——轴承系统为模型,导出了动力响应问题摄动R iccati传递矩阵法的具体计算公式,并编制了相应的计算分析程序。算例对弹性支承的等截面梁的动力响应问题进行了摄动分析,摄动计算结果和精确计算结果吻合良好。     

Dynamics of a viscoelastic rotor shaft using augmenting thermodynamic fields—A finite element approach

Modelling viscoelastic materials is always difficult since such materials store energy as well as dissipate it to the thermal domain. Whereas modelling the elastic behaviour is easy, modelling the energy dissipation mechanism poses difficulty. This paper presents a theoretical study of the dynamics of a viscoelastic rotor-shaft system, where the internal material damping in the rotor-shaft introduces a rotary force well known to cause instability of the rotor-shaft system. An efficient modelling technique that assumes coupled (thermo-mechanical) augmenting thermodynamic field (ATF) to derive the constitutive relationships is found more suitable in comparison with the viscous and hysteric damping models, and is used to model the viscoelastic rotor material. Dynamic behaviour of an aluminium rotor is predicted through viscoelastic modelling of the continuum to take into account the effect of internal material damping. Stability limit speed (SLS) and unbalance response (UBR) amplitude are used as two indices to study the dynamics. It is observed that, the ATF approach predicts more reliable SLS and UBR amplitude in comparison with the viscous and hysteretic model of rotor-internal damping. Composite rotor-shaft assumed by reinforcing the aluminium matrix with carbon fibre is found to postpone the critical speeds and thus make available, higher speed of rotor operation and lower UBR amplitude in comparison with pure aluminium rotor-shaft. Finite element method is used for modelling and analysis.     

转子在非惯性系中的动力学建模

以Jeffcott转子为模型,对其在非惯性系中进行了动力学研究.提出在非惯性系中,对于转子应考虑非惯性力和陀螺力矩的影响,采用包括陀螺近似原理在内的一些相关理论来分析.文中从非惯性参考系中质点的运动微分方程出发,推导出转子考虑非惯性力及陀螺力矩影响条件下的盘心运动分量方程函数.在模型建立过程中,还考虑了转子的偏心、初弯和阻尼力.这对进一步在非惯性系中研究转子的动力特性有一定的裨益.     

动力响应问题的一阶摄动传递矩阵法

基于Riccati传递矩阵法，给出了一维不确定参数结构系统动力响应问题的一阶摄动计算方法。该方法在用于求解一维结构系统动力响应问题时，不需要按振型展开，因此，可以避免基于有限元法的矩阵摄动所带来的模态截断误差问题，从而提高分析结果的精度。算例对简支梁和锅炉给水泵转子的动力响应问题进行了一阶摄动分析；当ε较小时，一阶摄动计算结果和精确计算结果吻合良好。