... this rotation force. Another method is the use of a unidirectional excitation and a mathematical operation to distinguish the forward whirl from the backward whirl. In this method, a directional frequency response function that separates the two modes in the frequency domain is obtained from four frequency...

... a desired reserve capacity for frequency response as specified. 28 04 2011 28 04 2011 04 11 2011 04 11 2011 The mathematical model of the system was calibrated with measured and calculated performance data using least square polynomial curve fitting and nonlinear parameter...

... force must be kept constant at a known value on every blade during step-sine test to calculate frequency response functions. The issue of the force control is therefore addressed since the performance of the electromagnet changes with frequency. The system calibration procedure and the estimated errors...

.... The first approach generates frequency response functions (FRFs) from the finite element case model at the bearing support locations. A high-order polynomial in numerator-denominator transfer function format is generated from a curve fit of the FRF. These transfer functions are then incorporated...

... the capability of analyzing bladed disks with pronounced frequency veering effects. The method allows the use of industrial-size sector models of bladed disks for analysis of forced response of a mistuned structure. The frequency response function matrix of a structurally mistuned bladed disk is derived...

... measuring system. An ambient temperature centrifugal compressor rig acts as an experimental source of fluctuating pressure. The compressor is operated at different discrete rotational speeds, and the blade-passing frequencies are used to obtain frequency response data. In the experiments, pressure waves...

... an otherwise accurate engineering model of the system in combination with available measurements of system frequency response functions. The approach permits treatment of flexible rotors and allows that the system test excitations and measurement sensors are not collocated. Because all engineering models...

... 1, 2004. IGTI Review Chair: A. J. Strazisar. 13 June 2004 01 October 2003 01 March 2004 24 06 2005 frequency response electric machines lubricating oils rotors machine bearings dynamic response frequency-domain analysis hydrodynamics vibrations Rotating...

...J. Eckstein; E. Freitag; C. Hirsch; T. Sattelmayer; R. von der Bank; T. Schilling The low-frequency response of the spray from a generic airblast diffusion burner with a design typical of an engine system has been investigated as part of an experimental study to describe the combustion oscillations...

... row-sum norm of the system frequency response matrix. The minimization of this norm is treated through the formulation of a set of linear matrix inequalities that can also incorporate design parameter constraints and stability criteria. The formulation can also be extended to cover uncertain or time...

... is then used to design the control system of the active bearing based on root locus curves. The active system stability is analyzed by calculating its eigenvalues and frequency response curves. The theoretical and experimental results show that this kind of bearing can significantly reduce the vibration level...

...J. A. Va´zquez; E. H. Maslen; H.-J. Ahn; D.-C. Han The experimental identification of a long flexible rotor with three magnetic bearing journals is presented. Frequency response functions are measured between the magnetic bearing journals and the sensor locations while the rotor is suspended...

... in the approximation process and the weighting coefficients are determined by using a simple recurrence relationship instead of solving a set of linear algebraic equations. turbines dynamics vibrations frequency response eigenvalues and eigenfunctions engineering computing numerical analysis 04...

... the frequency response function (FRF) matrix of the tuned system and a matrix describing the mistuning. The main advantages of the method are its efficiency and accuracy, which allow the use of large finite element models of practical bladed disk assemblies in parametric studies of mistuning effects...

... and instrumentation used to monitor and diagnose problems associated with rolling element bearing machinery. machine bearings flaw detection displacement measurement transducers vibrations frequency response 04 June 2001 01 Sept 2000 01 Mar 2001 19 06 2002 Contributed...

...D. Moro; N. Cavina; F. Ponti, DIEM This paper presents an original methodology for the instantaneous in-cylinder pressure waveform reconstruction in a spark-ignited internal combustion engine. The methodology is based on the existence of a linear correlation, characterized by frequency response...

... received by the ASME Headquarters June 9, 1999. Editor: H. D. Nelson. 04 May 1999 09 June 1999 rotors turbines vibrations vibrational modes modal analysis identification parameter estimation frequency response elasticity mass In regards to the maximum likelihood (ML...

... vibrations vibrational modes modal analysis identification parameter estimation frequency response elasticity mass A large number of investigations have focused, in the last thirty years, on the assessment of the effects of mistuning, i.e., small blade-to-blade variations of their mechanical...