Inducing and monitoring a vibratory response in a component

1. A system for testing a component, comprising:

a support structure configured to support the component;

a stationary base structure, wherein the support structure is attached to the stationary base structure through a compliant connection;

an excitation system including

a plurality of permanent magnets arranged in an array and configured for rigid connection to the component, and

a plurality of electromagnets comprising a first electromagnet, a second electromagnet and a third electromagnet, each of the electromagnets associated with a respective one of the permanent magnets,

the excitation system configured to respectively control interaction of the electromagnets with the permanent magnets to excite a vibratory response in the component; and

a sensor system configured to output data indicative of the vibratory response.

2. The system of claim 1 , wherein the support structure comprises a mount for rigidly attaching the component to the support structure.

3. The system of claim 1 , wherein the electromagnets are connected to the stationary base structure.

4. The system of claim 1 , wherein each of the permanent magnets is attached to the support structure and thereby configured for rigid connection to the component through the support structure.

5. The system of claim 1 , wherein the excitation system is configured to change a parameter of a magnetic field generated by one of the electromagnets according to a function.

6. The system of claim 5 , wherein the parameter comprises strength of the magnetic field.

7. The system of claim 5 , wherein the parameter comprises phase of the magnetic field.

8. The system of claim 5 , wherein the parameter comprises frequency of oscillations in the magnetic field.

9. The system of claim 5 , wherein the function is a sinusoidal function.

10. The system of claim 1 , wherein

the excitation system is configured to vary strength, frequency of oscillations and phase of a first magnetic field generated by the first electromagnet according to a function;

the excitation system is further configured to vary strength, frequency of oscillations and phase of a second magnetic field generated by the second electromagnet according to the function; and

the varying of the strength, the frequency of oscillations and the phase of the first magnetic field is out of phase with the varying of the strength, the frequency of oscillations and the phase of the second magnetic field.

11. The system of claim 10 , wherein

the excitation system is further configured to vary strength, frequency of oscillations and phase of a third magnetic field generated by the third electromagnet according to the function; and

the varying of the strength, the frequency of oscillations and the phase of the first magnetic field is in phase with the varying of the strength, the frequency of oscillations and the phase of the third magnetic field.

12. The system of claim 10 , wherein

the excitation system is further configured to vary strength, frequency of oscillations and phase of a third magnetic field generated by the third electromagnet according to the function; and

the varying of the strength, the frequency of oscillations and the phase of the third magnetic field is out of phase with the varying of the strength, the frequency of oscillations and the phase of the first magnetic field and the varying of the strength, the frequency of oscillations and the phase of second magnetic field.

13. The system of claim 1 , further comprising a rotor and a motor configured to drive rotation of the rotor about an axis, wherein the rotor is configured for forming a lift off seal system with the component.

14. The system of claim 1 , wherein the sensor system comprises a plurality of accelerometers arranged in an array and configured for rigid connection to the component, and the accelerometers are configured to sense the vibratory response of the component.

15. A method for testing a component, comprising:

supporting the component with a supporting structure where the supporting structure is attached to a stationary base structure through a compliant connection;

arranging the component with an excitation system where the excitation system includes a plurality of permanent magnets and a plurality of electromagnets comprising a first electromagnet, a second electromagnet and a third electromagnet, wherein each of the electromagnets is configured to interact with a respective one of the permanent magnets, and the permanent magnets are rigidly connected to the component after the arranging;

exciting a vibratory response in the component by operating the excitation system to respectively control interaction of the electromagnets with the permanent magnets; and

outputting data indicative of the vibratory response from a sensor system.

16. The method of claim 15 , further comprising processing the data with a computer system to determine at least one of a structural characteristic or a dynamic response characteristic of the component.

17. The method of claim 15 , wherein the operating of the excitation system to control the interaction of the electromagnets with the permanent magnets comprises varying strength, frequency of oscillations and phase of a first magnetic field generated by the first electromagnet according to a function.

18. The method of claim 17 , wherein

the operating of the excitation system to control the interaction of the electromagnets with the permanent magnets further comprises varying strength, frequency of oscillations and phase of a second magnetic field generated by the second electromagnet according to the function; and

the varying of the strength, the frequency of oscillations and the phase of the first magnetic field is out of phase with the varying of the strength, the frequency of oscillations and the phase of the second magnetic field.

19. The method of claim 15 , further comprising rotating a rotor about an axis, wherein the rotor and the component form a lift off seal system.