Frequency shifting isolator system

• US 20060178859A1
• Filed: 02/04/2005
• Published: 08/10/2006
• Est. Priority Date: 02/04/2005
• Status: Active Grant

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Monson, Robert J., Neuman, Julia A., Yan, Jianhua
• Granted Patent: US 7,415,397 B2
• Time in Patent Office: Days
• US Class Current: 703/6
• CPC Class Codes: F16F 15/00 Suppression of vibrations in systems damping of non-rotary systems using inertia effect F16F7/10; prevention or isolation of vibrations in machine tools B23Q11/0032; suppression of driveline vibrations in hybrid vehicle transmissions B60W30/20 ; vehicle seat suspension devices B60N2/50; methods or devices for protecting against, or damping of, acoustic waves, e.g. sound G10K11/16; Means or arrangements for avoiding or reducing out-of-balance forces, e.g. due to motion vibration absorbing or balancing means for aircraft propellers B64C11/008, for rotorcraft rotors B64C27/001 ; testing static and dynamic balance of machines or structures G01M1/00
• CPC Class Codes: Y10T 428/233 Foamed or expanded material encased

Abstract

The present invention provides a method for designing a frequency-shifting isolator system that includes selecting, an impact absorption envelope; a geometry for the isolator mount system; and an elastomeric dampening material formed in the selected geometry. The isolator mount system is preferably configured to shift frequencies at predetermined displacements upon impact, at or before the system attains resonance.

Claims

1. A method for optimizing a frequency-shifting isolator, the steps comprising:

establishing a desired impact absorption envelope;

defining a set of structural system requirements within the desired impact absorption envelope;

selecting at least one geometry for the frequency shifting isolator that conforms to the set of structural system requirements; and

selecting a desired structural material formed in the at least one geometry, the material configured to shift frequencies at a plurality of displacements upon impact within the desired impact absorption envelope, such that the frequency shifts occur in association with displacement.

2. The method of claim 1, wherein the desired impact absorption envelope is determined from the displacement-natural frequency requirement of the isolator system.

3. The method of claim 2, wherein the displacement-natural frequency relationship is translated to form a displacement-spring constant requirement of the isolator system.

4. The method of claim 1, wherein the structural requirements of the frequency shifting isolator system are defined without regard to any force-displacement relationship.

5. The method of claim 1, wherein the selected geometry of the isolator system is determined without regard to any force-displacement relationship.

6. The method of claim 1, wherein the desired structural material configured in the selected geometry is further selected from three-dimensional shapes.

7. The method of claim 1, wherein the desired structural material comprises an elastomeric damping material.

8. The method of claim 1, wherein the selected geometry is non-linear such that the frequency-shifting isolator system exhibits virtually an infinite number of natural frequencies.

9. The method of claim 1, wherein the desired structural material comprises a non-linear material such that the frequency-shifting isolator system exhibits virtually an infinite number of natural frequencies.

10. The method of claim 1, wherein the step of establishing a desired impact absorption envelope comprises the steps of:

defining a frequency-shifting isolator system displacement-natural frequency requirement; and

translating the displacement-natural frequency requirement to a displacement-spring factor requirement.

11. The method of claim 1, wherein the step of defining a set of structural system requirements within the desired impact absorption envelope comprises the steps of:

establishing system weight of a sprung mass;

establishing shock and vibration input spectra; and

defining momentum constraints of the system.

12. The method of claim 1, wherein the step of selecting a geometry for the isolator system that conforms to the set of structural system requirements comprises the steps of:

formulating a structure capable of meeting the momentum constraints; and

modifying the structure to enable frequency shifting at appropriate displacements.

13. The method of claim 12, wherein the step of modifying the structure to enable frequency shifting at appropriate displacements comprises the steps of:

implementing the structure to incorporate desired buckling events;

implementing the structure to incorporate desired geometric characteristics; and

managing any overlap of the structural materials.

14. The method of claim 13, wherein the desired geometric characteristics comprise angles and thicknesses.

15. The method of claim 13, further comprising the step of analyzing the modified structure to ensure the system will have expected displacements under defined input conditions.

16. The method of claim 15, further comprising the step of analyzing the modified structure to ensure the system will have expected natural frequencies at expected displacements.

17. The method of claim 16, further comprising the step of producing a prototype frequency-shifting isolator system.

18. The method of claim 17, further comprising the step of producing an initial mount comprising the prototype frequency-shifting isolator system.

19. The method of claim 18, further comprising the step of empirically testing the mount to validate the design of the initial mount.

20. A method of designing a frequency-shifting isolator system, the method comprising the steps of:

defining requisite displacement-natural frequency requirements;

translating the requisite displacement-natural frequency requirements to displacement-spring factor requirements;

defining requisite frequency-shifting isolator system structural requirements based on the displacement-natural frequency requirements;

implementing at least one frequency-shifting isolator system structure that conforms to the structural requirements; and

modifying the at least one frequency-shifting isolator system structure to enable frequency shifting at desired displacements.

21. The method of claim 20, wherein the structural requirements of the frequency shifting isolator system are defined without regard to any force-displacement relationship.

22. The method of claim 20, wherein the step of defining requisite frequency-shifting isolator system structural requirements based on the displacement-natural frequency requirements comprises the steps of:

establishing system weight of a sprung mass;

establishing shock and vibration input spectra; and

defining momentum constraints of the system.

23. The method of claim 22, wherein the step of implementing at least one frequency-shifting isolator system structure that conforms to the structural requirements comprises the steps of:

formulating a structure capable of meeting the momentum constraints; and

modifying the structure to enable frequency shifting at desired displacements.

24. The method of claim 23, wherein the step of modifying the structure to enable frequency shifting at desired displacements comprises the steps of:

implementing the structure to incorporate desired buckling events;

implementing the structure to incorporate desired geometric characteristics; and

managing any overlap of structural materials.

25. The method of claim 20, further comprising the step of analyzing the modified structure to ensure the system will have expected displacements under defined input conditions.

26. The method of claim 25, further comprising the step of analyzing the modified structure to ensure the system will have expected natural frequencies at expected displacements.

27. The method of claim 26, further comprising the step of producing a prototype frequency-shifting isolator system.

28. The method of claim 27, further comprising the step of producing an initial mount comprising the prototype frequency-shifting isolator system.

29. The method of claim 28, further comprising the step of empirically testing the mount to validate the design of the initial mount.

30. The method of claim 20, wherein the step of implementing at least one frequency-shifting isolator system structure that conforms to the structural requirements comprises implementing at least one frequency-shifting isolator system structure via a non-linear geometry such that the system exhibits virtually an infinite number of natural frequencies.

31. The method of claim 20, wherein the step of implementing at least one frequency-shifting isolator system structure that conforms to the structural requirements comprises implementing at least one frequency-shifting isolator system structure via a non-linear material such that the system exhibits virtually an infinite number of natural frequencies.

32. The method of claim 20, wherein the step of implementing at least one frequency-shifting isolator system structure that conforms to the structural requirements comprises implementing at least one frequency-shifting isolator system structure via an elastomeric damping material.