Refinement of finite element model of integrally bladed disk
A reduced order model of an integrally bladed turbine disk (IBD) is used with experimental vibrational test data to modify a finite element model (FEM) of the IBD so that the FEM more accurately predicts the vibrational mistuning of the disk. The refined FEM can be used to evaluate a proposed modification of the IBD before the hardware is actually modified, and to evaluate the actual modification if there is a difference between the proposed and actual modifications.
1. A method comprising using a reduced order model of a component and vibratory test data of the component to refine a finite element model of the component, wherein the component is an integrally bladed disk (IBD), further comprising:
measuring dimensions of the IBD;
constructing a geometrically mistuned finite element model of the IBD to reflect the measured dimensions;
obtaining a reduced order model of the IBD reflecting characteristics of the IBD output from the geometrically mistuned finite element model;
measuring an actual vibratory response of the IBD;
using the actual vibratory response as input to the reduced order model to calculate a residual mistuning of the IBD not predicted by the geometrically mistuned finite element model; and
refining the geometrically mistuned finite element model to reduce the residual mistuning.
2. The method of claim 1 , further comprising using the refined finite element model to evaluate a proposed modification of the component.
3. The method of claim 1 , wherein the step of refining the geometrically mistuned finite element model comprises changing a density of a segment in the geometrically mistuned finite element model.
4. The method of claim 1 , wherein the step of refining the geometrically mistuned finite element model comprises changing a dimension of a segment in the geometrically mistuned finite element model.
5. The method of claim 1 , wherein the step of refining the geometrically mistuned finite element model comprises changing a modulus of a segment in the geometrically mistuned finite element model.
6. The method of claim 1 , further comprising using the refined geometrically mistuned finite element model to evaluate a change in geometry of the IBD.
7. The method of claim 1 , further comprising using the refined geometrically mistuned finite element model to evaluate a change in geometry of the IBD before the change is actually implemented on the IBD.
8. The method of claim 7 , wherein the change in geometry is a blend, and further comprising:
proposing the blend in the IBD;
using the refined geometrically mistuned finite element model to evaluate the IBD with the proposed blend; and
implementing the proposed blend in the IBD only if the evaluation of the IBD with the proposed blend is acceptable.
9. A method comprising using a reduced order model of a component and vibratory test data of the component to refine a finite element model of the component, wherein the component is an integrally bladed disk (IBD), further comprising:
measuring a vibration signature of the IBD responsive to an excitation;
calculating mistuned blade frequencies of the IBD using the vibration signature as an input to a reduced order model of the IBD;
calculating mistuned blade frequencies of the IBD using a finite element model of the IBD;
comparing the mistuned blade frequencies of the IBD calculated with the reduced order model and the mistuned blade frequencies of the IBD calculated with the finite element model to determine a residual mistuning; and
refining the finite element model to reduce the residual mistuning.
10. The method of claim 9 , wherein the step of refining the finite element model comprises changing a density of a segment in the finite element model.
11. The method of claim 9 , wherein the step of refining the finite element model comprises changing a dimension of a segment in the finite element model.
12. The method of claim 9 , wherein the step of refining the finite element model comprises changing a modulus of a segment in the finite element model.
13. The method of claim 9 , further comprising:
constructing a geometrically mistuned finite element model of the IBD to reflect measured dimensions of the IBD;
using the geometrically mistuned finite element model in the step of calculating mistuned blade frequencies of the IBD using the finite element model; and
refining the geometrically mistuned finite element model to reduce the residual mistuning.
14. The method of claim 9 , further comprising using the refined finite element model to evaluate a change in geometry of the IBD.
15. The method of claim 9 , further comprising using the refined finite element model to evaluate a change in geometry of the IBD before the change in geometry is actually implemented on the IBD.
16. The method of claim 15 , wherein the change in geometry is a blend, and further comprising:
proposing the blend in the IBD;
using the refined finite element model to evaluate the IBD with the proposed blend; and
implementing the proposed blend in the IBD only if the evaluation of the IBD with the proposed blend is acceptable.