Experimental Investigation of Geometric Uncertainty Effects on Blade Forced Response

2004 ◽  
Author(s):  
Ryan O'Hara ◽  
Jeffrey Brown
Keyword(s):  
Experimental Investigation ◽  
Forced Response ◽  
Geometric Uncertainty

Stability and Stationary Response of a Skew Jeffcott Rotor With Geometric Uncertainty

2009 ◽  
Vol 4 (2) ◽  
Author(s):  
Nicolas Driot ◽  
Alain Berlioz ◽  
Claude-Henri Lamarque
Keyword(s):  
Equations Of Motion ◽  
Dynamical Behavior ◽  
Forced Response ◽  
Stochastic Methods ◽  
Steady State Response ◽  
State Response ◽  
Internal Excitation ◽  
Geometric Uncertainty ◽  
Jeffcott Rotor ◽  
Support Motion

The aim of this work is to apply stochastic methods to investigate uncertain parameters of rotating machines with constant speed of rotation subjected to a support motion. As the geometry of the skew disk is not well defined, randomness is introduced and affects the amplitude of the internal excitation in the time-variant equations of motion. This causes uncertainty in dynamical behavior, leading us to investigate its robustness. Stability under uncertainty is first studied by introducing a transformation of coordinates (feasible in this case) to make the problem simpler. Then, at a point far from the unstable area, the random forced steady state response is computed from the original equations of motion. An analytical method provides the probability of instability, whereas Taguchi’s method is used to provide statistical moments of the forced response.

Experimental Investigation of Mode Localization and Forced Response Amplitude Magnification for a Mistuned Bladed Disk

2000 ◽  
Author(s):  
John Judge ◽  
Christophe Pierre ◽  
Oral Mehmed
Keyword(s):  
Experimental Investigation ◽  
Traveling Wave ◽  
Forced Response ◽  
Response Amplitude ◽  
Mode Shapes ◽  
Bladed Disks ◽  
Element Analysis ◽  
Mode Localization ◽  
Bladed Disk ◽  
Out Of Plane

The results of an experimental investigation on the effects of random blade mistuning on the forced dynamic response of bladed disks are reported. The primary aim of the experiment is to gain understanding of the phenomena of mode localization and forced response blade amplitude magnification in bladed disks. A stationary, nominally periodic, twelve-bladed disk with simple geometry is subjected to a traveling-wave, out-of-plane, “engine order” excitation delivered via phase-shifted control signals sent to piezo-electric actuators mounted on the blades. The bladed disk is then mistuned by the addition of small, unequal weights to the blade tips, and it is again subjected to a traveling wave excitation. The experimental data is used to verify analytical predictions about the occurrence of localized mode shapes, increases in forced response amplitude, and changes in resonant frequency due to the presence of mistuning. Very good agreement between experimental measurements and finite element analysis is obtained. The out-of-plane response is compared and contrasted with the previously reported in-plane mode localization behavior of the same test specimen. This work also represents an important extension of previous experimental study by investigating a frequency regime in which modal density is lower but disk-blade interaction is significantly greater.

scholarly journals An Experimental Investigation of Vibration Localization in Bladed Disks: Part II — Forced Response

1997 ◽  
Author(s):  
Marlin J. Kruse ◽  
Christophe Pierre
Keyword(s):  
Experimental Investigation ◽  
Forced Response ◽  
Mode Shapes ◽  
Bladed Disks ◽  
Structural Coupling ◽  
Vibration Localization ◽  
Bladed Disk ◽  
Engine Order ◽  
Localized Mode ◽  
The Impact

The results of an experimental investigation on the effects of random blade mistuning on the forced dynamic response of bladed disks are reported. Two experimental specimens are considered: a nominally periodic twelve-bladed disk with equal blade lengths, and the corresponding mistuned bladed disk, which features slightly different blades of random lengths. Both specimens are subject to traveling-wave excitations delivered by piezo-electric actuators. The primary aim of the experiment is to demonstrate the occurrence of an increase in forced response blade amplitudes due to mistuning, and to verify analytical predictions about the magnitude of these increases. In particular, the impact of localized mode shapes, engine order excitation, and disk structural coupling on the sensitivity of forced response amplitudes to blade mistuning is reported. This work reports one of the first systematic experiments carried out to demonstrate and quantify the effect of mistuning on the forced response of bladed disks.

Experimental Investigation on the Forced Response of a Dummy Counter Rotating Turbine Stage With Friction Damping

2012 ◽  
Author(s):  
Teresa Berruti ◽  
Vanni Maschio ◽  
Paolo Calza
Keyword(s):  
Experimental Investigation ◽  
Dynamic Behavior ◽  
Dry Friction ◽  
Vibration Damping ◽  
Forced Response ◽  
Test Results ◽  
Turbine Stage ◽  
Friction Damping ◽  
Experimental Activity ◽  
Open Rotor

The paper shows the results of the experimental activity about the dynamics of a stage of a counter rotating turbine of an open rotor architecture engine. The tests here presented explore the dynamic behavior of a simplified counter-rotating turbine stage. The test results show the dynamic behavior of a counter rotating turbine stage and highlight the importance of the presence of dry friction for vibration damping.

Probabilistic Analysis of Geometric Uncertainty Effects on Blade Modal Response

2003 ◽  
Author(s):  
Jeffrey M. Brown ◽  
Joeseph Slater ◽  
Ramana V. Grandhi
Keyword(s):  
Approximation Error ◽  
Principal Component ◽  
Monte Carlo Sampling ◽  
Forced Response ◽  
Coordinate Measurement ◽  
Modal Response ◽  
Geometric Uncertainty ◽  
Spatial Geometry ◽  
Variable Space ◽  
Blade Frequency

This paper investigates the effect of manufacturing variations on the modal response of a transonic low aspect ratio fan. A simulated set of coordinate measurement machine measurements from a single rotor, representative of actual manufacturing variations, are used to investigate geometric effects. Principal component analysis is used to statistically model spatial geometry variations and reduce variable space dimensionality. Statistics from this analysis are used with Monte Carlo sampling to generate random blades realizations that are used to predict response distributions for a simulated fleet of 1000 blades. An existing approach to approximate blade frequency response is extended to include modal displacement and stress. These approximations are based on eigensensitivity analysis and first order Taylor series approximations. An approximation error analysis is conducted to quantify accuracy. The effect of small geometry variations on blade natural frequency, mode shape, and modal stress is investigated with results showing that small variations on the order of mils can cause significant variations in both scale and location of free and forced response.

Experimental Investigation on the Forced Response of a Dummy Counter-Rotating Turbine Stage With Friction Damping

2012 ◽  
Vol 134 (12) ◽  
Author(s):  
Teresa Berruti ◽  
Vanni Maschio
Keyword(s):  
Experimental Investigation ◽  
Dynamic Behavior ◽  
Dry Friction ◽  
Vibration Damping ◽  
Forced Response ◽  
Test Results ◽  
Turbine Stage ◽  
Friction Damping ◽  
Experimental Activity ◽  
Open Rotor

The paper shows the results of the experimental activity about the dynamics of a stage of a counter-rotating turbine of an open rotor architecture engine. The tests presented here explore the dynamic behavior of a simplified counter-rotating turbine stage. The test results show the dynamic behavior of a counter-rotating turbine stage and highlight the importance of the presence of dry friction for vibration damping.

Sign in / Sign up

Export Citation Format

Share Document