Traveling Wave Excitation: A Method to Produce Consistent Experimental Results

2014 ◽  
Vol 136 (12) ◽  
Author(s):  
Geofrey S. Cox ◽  
Anthony N. Palazotto ◽  
Jeffrey M. Brown ◽  
Tommy J. George
Keyword(s):  
Traveling Wave ◽  
Forced Response ◽  
Test Stand ◽  
Experimental Results ◽  
Wave Excitation ◽  
Alignment Position ◽  
Excitation System ◽  
Response Measurement ◽  
Signal Input

This paper describes the experimental framework to establish consistent, repeatable results associated with a traveling wave excitation system. The experiment is employed to ascertain the forced response and mistuning patterns for rotors. Several items attributing to existing experimental inconsistencies were identified and their effects were realized during this research. These experimental items were signal input locations, response measurement locations, and rotor alignment position. Accounting for these experimental variables, this paper develops a process which enables consistent rotor forced response results, independent of its orientation on the test stand.

A Test Rig for Noncontact Traveling Wave Excitation of a Bladed Disk With Underplatform Dampers

2010 ◽  
Vol 133 (3) ◽  
Author(s):  
Teresa Berruti ◽  
Christian M. Firrone ◽  
Muzio M. Gola
Keyword(s):  
Traveling Wave ◽  
Numerical Models ◽  
Experimental Tests ◽  
Calibration Procedure ◽  
Forced Response ◽  
Wave Excitation ◽  
Test Rig ◽  
Response Measurement ◽  
Static Test ◽  
Bladed Disk

This paper presents a static test rig called “Octopus” designed for the validation of numerical models aimed at calculating the nonlinear dynamic response of a bladed disk with underplatform dampers (UPDs). The test rig supports a bladed disk on a fixture and each UPD is pressed against the blade platforms by wires pulled by dead weights. Both excitation system and response measurement system are noncontacting. This paper features the design and the setup of the noncontacting excitation generated by electromagnets placed under each blade. A traveling wave excitation is generated according to a desired engine order by shifting the phase of the harmonic force of one electromagnet with respect to the contiguous exciters. Since the friction phenomenon generated by UPDs introduces nonlinearities on the forced response, the amplitude of the exciting 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 on the generated force are also presented. Examples of experimental tests that can be performed on a dummy integral bladed disk (blisk) mounted on the rig are described in the end.

Next Generation Traveling Wave Excitation System for Integrally Bladed Rotors

2014 ◽  
Author(s):  
Joseph Beck ◽  
John A. Justice ◽  
Onome Scott-Emuakpor ◽  
Tommy George
Keyword(s):  
Traveling Wave ◽  
Wave Excitation ◽  
Next Generation ◽  
Excitation System

Next Generation Traveling-Wave Excitation System for Integrally Bladed Rotors

2015 ◽  
Vol 28 (6) ◽  
pp. 04015005 ◽  
Author(s):  
Joseph A. Beck ◽  
John A. Justice ◽  
Onome E. Scott-Emuakpor ◽  
Tommy J. George ◽  
Jeffrey M. Brown
Keyword(s):  
Traveling Wave ◽  
Wave Excitation ◽  
Next Generation ◽  
Excitation System

A Test Rig for Non-Contact Travelling Wave Excitation of a Bladed Disk With Underplatform Dampers

2010 ◽  
Author(s):  
Teresa Berruti ◽  
Christian M. Firrone ◽  
Muzio M. Gola
Keyword(s):  
Numerical Models ◽  
Experimental Tests ◽  
Calibration Procedure ◽  
Travelling Wave ◽  
Forced Response ◽  
Wave Excitation ◽  
Test Rig ◽  
Response Measurement ◽  
Static Test ◽  
Bladed Disk

The paper presents a static test rig called “Octopus” designed for the validation of numerical models aimed at calculating the nonlinear dynamic response of a bladed disk with underplatform dampers (UPDs). The test rig supports a bladed disk on a fixture and each UPD is pressed against the blade platforms by wires pulled by dead weights. Both excitation system and response measurement system are noncontacting. The paper features the design and the set-up of the noncontacting excitation generated by electromagnets placed under each blade. A travelling wave excitation is generated according to a desired engine order by shifting the phase of the harmonic force of one electromagnet with respect to the contiguous exciters. Since the friction phenomenon generated by UPDs introduces nonlinearities on the forced response, the amplitude of the exciting 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 on the generated force are also presented. Examples of experimental tests that can be performed on a dummy integral bladed disk (blisk) mounted on the rig are described in the end.

Traveling Wave Excitation System for Bladed Disks

2003 ◽  
Vol 19 (1) ◽  
pp. 135-141 ◽  
Author(s):  
Keith W. Jones ◽  
Charles J. Cross
Keyword(s):  
Traveling Wave ◽  
Wave Excitation ◽  
Excitation System ◽  
Bladed Disks

Experimental Demonstration of Maximum Mistuned Bladed Disk Forced Response

2003 ◽  
Vol 125 (4) ◽  
pp. 673-681 ◽  
Author(s):  
J. A. Kenyon ◽  
J. H. Griffin
Keyword(s):  
Traveling Wave ◽  
Close Agreement ◽  
Maximum Amplitude ◽  
Forced Response ◽  
Maximum Response ◽  
Experimental Demonstration ◽  
Wave Excitation ◽  
Bladed Disk ◽  
Engine Order ◽  
Structural Mode

A theory was previously developed for predicting robust maximum forced response in mistuned bladed disks from distortion of a structural mode. This paper describes an experiment to demonstrate the theory. A bladed disk is designed to be sufficiently sensitive to mistuning to obtain maximum response. The maximum amplitude magnification from mistuning is predicted using the theory, 1.918. The bladed disk is intentionally mistuned to obtain the maximum response, and the response to an engine order traveling wave excitation is measured. The measured amplitude magnification is in close agreement with the theory. The robustness of the maximum response is demonstrated.

Experimental Demonstration of Maximum Mistuned Bladed Disk Forced Response

2003 ◽  
Author(s):  
J. A. Kenyon ◽  
J. H. Griffin
Keyword(s):  
Traveling Wave ◽  
Close Agreement ◽  
Maximum Amplitude ◽  
Forced Response ◽  
Maximum Response ◽  
Experimental Demonstration ◽  
Wave Excitation ◽  
Bladed Disk ◽  
Engine Order ◽  
Structural Mode

A theory was previously developed for predicting robust maximum forced response in mistuned bladed disks from distortion of a structural mode. This paper describes an experiment to demonstrate the theory. A bladed disk is designed to be sufficiently sensitive to mistuning to obtain maximum response. The maximum amplitude magnification from mistuning is predicted using the theory, 1.918. The bladed disk is intentionally mistuned to obtain the maximum response, and the response to an engine order traveling wave excitation is measured. The measured amplitude magnification is in close agreement with the theory. The robustness of the maximum response is demonstrated.

Generalized Linford formula and its application to Traveling Wave Excitation

2001 ◽  
Vol 11 (PR2) ◽  
pp. Pr2-285-Pr2-288
Author(s):  
R. Tommasini ◽  
E. E. Fill
Keyword(s):  
Traveling Wave ◽  
Wave Excitation
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