Shape changing structure

• US 20060124801A1
• Filed: 11/12/2004
• Published: 06/15/2006
• Est. Priority Date: 11/12/2004
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Wood, Jeffrey H.
• Granted Patent: US 7,216,831 B2
• Time in Patent Office: Days
• US Class Current: 244/53.R
• CPC Class Codes: F02K 1/1207 of one series of flaps hinged at their upstream ends on a fixed structure F02K1/1215 - F02K1/1292 take precedence
• CPC Class Codes: F02K 1/123 of two series of flaps, both having their flaps hinged at their upstream ends on a fixed structure
• CPC Class Codes: F02K 1/386 mixing devices in the jet pipe, e.g. for mixing primary and secondary flow
• CPC Class Codes: F02K 1/48 Corrugated nozzles
• CPC Class Codes: F02K 9/805 servo-mechanisms or control devices therefor
• CPC Class Codes: F05D 2300/505 Shape memory behaviour

Abstract

In one preferred embodiment, a structure is provided that includes a body having a first wall and a second wall. At least one appending component extends from an end of the body and includes a first skin and second skin. The structure additionally includes at least one actuator positioned within a cavity formed in the body first wall and the appending component second skin. The actuator includes at least one shape memory alloy (SMA) wire adapted to constrict when activated to move the first skin of the appending component from a first position to a second position.

Claims

1. A structure comprising:

a body including a first wall and a second wall;

at least one appending component extending from an end of the body, the appending component including a first skin and second skin; and

at least one actuator positioned within a cavity formed in the first wall and the second skin, the actuator comprising at least one shape memory alloy (SMA) wire adapted to constrict when activated to move the first skin of the appending component from a first position to a second position.

2. The structure of claim 1, wherein a proximal end of the appending component first skin is coupled to an edge portion of the first wall, a proximal end of the appending component second skin is coupled to an edge portion of the second wall, and a distal end of the first skin being in firm contact with a distal end of the second skin.

3. The structure of claim 1, wherein the actuator further comprises a fixed pulling bracket coupled to an interior side of the first wall, between the first and second walls and within the cavity.

4. The structure of claim 3 wherein the actuator further comprises a free pulling bracket located between the first and second walls and within the cavity, the free pulling bracket adapted to be movable within the cavity.

5. The structure of claim 4, wherein the actuator further comprises a control arm connected at a control arm first end to the free pulling bracket and at a control arm second end to a deployment cam linkage.

6. The structure of claim 5, wherein the SMA wire is coupled at a SMA wire first end to the fixed pulling bracket and coupled at a SMA wire second end to the free pulling bracket such that when the SMA wire constricts the free pulling bracket and control arm are pulled toward the fixed pulling bracket to thereby cause a lever plate of the deployment cam linkage to force the distal end of the appending component first skin to separate from the distal end of the appending component second skin and move appending component first skin from a first position to a second position.

7. The structure of claim 6, wherein the SMA wire comprises swaged fittings connected to the SMA wire first and second ends to couple the SMA wire to the fixed pulling bracket and the free pulling bracket.

8. The structure of claim 1, wherein the SMA wire is activated by an increase in temperature of air flowing adjacent the body first wall and the appending component first skin.

9. The structure of claim 8, wherein the SMA wire is deactivated by a decrease in temperature of the air flow.

10. The structure of claim 1, wherein the SMA wire is activated by connecting the SMA wire to an electrical current source such that current flows through the SMA wire.

11. The structure of claim 10, wherein the SMA wire is deactivated by disconnecting the SMA wire from the electrical current source such that the current no longer flows through the SMA wire.

12. The structure of claim 10, wherein the actuator comprises a plurality of SMA wires electrically connected by jumpers such that the current flows through all the SMA wires when activated.

13. The structure of claim 1, wherein the appending component first skin acts as a biasing device to return the appending component first skin to the first position when the SMA wire is deactivated.

14. The structure of claim 1, wherein the body comprises a jet engine nacelle.

15. The structure of claim 14, wherein the appending component comprises an exhaust mixing tab adapted to intermix an exhaust from the nacelle with ambient air flowing adjacent the nacelle.

16. A method for altering the position of an exhaust mixing structure extending from an end of a jet engine nacelle nozzle, said method comprising:

attaching a fixed pulling bracket of at least one actuator to the nozzle within a cavity formed in an outer wall of the nozzle and an outer skin of the exhaust mixing structure;

coupling a control arm between a free pulling bracket of the actuator and an upper plate of a deployment cam linkage, the free pulling bracket of the actuator being movable within the cavity; and

activating at least one shape memory alloy (SMA) tendon connected between the actuator fixed and free pulling brackets such that the SMA tendon longitudinally constricts to pull the free pulling bracket and the control arm toward the fixed pulling bracket to cause the deployment cam linkage to move an inner skin of the exhaust mixing structure from a first position to a second position.

17. The method of claim 16, wherein attaching the fixed pulling bracket of the actuator to the nozzle comprises coupling the fixed pulling bracket to an interior side of an inner wall of the nozzle, between the inner wall and an outer wall of the nozzle and within the cavity.

18. The method of claim 17, wherein activating the SMA tendon comprises activating the SMA tendons such that the inner skin of the exhaust mixing structure is moved from the first position, wherein a distal end portion of the inner skin being in firm contact with a distal end portion of an outer skin of the exhaust mixing structure, to the second position, wherein the inner skin distal end portion is separated from the outer skin distal end portion.

19. The method of claim 18, wherein activating the SMA tendon comprises:

coupling a first end of the SMA tendon to the fixed pulling bracket by retaining a swaged fitting connected to the SMA tendon first end within the fixed pulling bracket; and

coupling a second end of the SMA tendon to the free pulling bracket by retaining a swaged fitting connected to the SMA tendon second end within the free pulling bracket.

20. The method of claim 16, wherein the method further comprises deactivating the SMA tendon causing the SMA tendon to relax and allow a biasing component of the exhaust mixing structure to return the exhaust mixing structure inner skin from the second position to the first position.

21. The method of claim 20, wherein activating SMA tendon comprises increasing a temperature of a nozzle exhaust flowing adjacent the inner wall of the nozzle and the inner skin of the exhaust mixing structure causing the SMA tendon to longitudinally constrict.

22. The method of claim 21, wherein deactivating the SMA tendon comprises decreasing a temperature of ambient air flowing adjacent the outer wall of the nozzle and the outer skin of the exhaust mixing structure causing the SMA tendon to relax and allow the biasing component to return the exhaust mixing structure inner skin to the first position.

23. The method of claim 20, wherein activating SMA tendon comprises connecting the SMA tendon to an electrical current source such that current flows through the SMA tendon to heat the SMA tendon causing the SMA tendon to longitudinally constrict.

24. The method of claim 23, wherein deactivating the SMA tendon comprises disconnecting the SMA tendon from the electrical current source causing the SMA tendon to relax and allow the biasing component to return the exhaust mixing structure inner skin to the first position.

25. The method of claim 20, wherein deactivating the SMA tendon comprises utilizing the inner skin of the exhaust mixing structure as the biasing component.

26. A jet engine adapted to controllably alter a flow of exhaust emitted from a nacelle of the engine, said engine comprising:

a nacelle nozzle having a body including an inner wall and an outer wall;

a plurality of flow altering structures extending from an end of the nozzle body, each flow altering structure comprising;

an inner skin fixedly coupled at a proximal end to an edge portion of the nozzle body inner wall; and

an outer skin fixedly coupled at a proximal end to an edge portion of the nozzle body outer wall, a distal end of the inner skin being in firm contact with a distal end of the outer skin; and

a plurality of actuators positioned within a plurality of cavities formed in the nozzle body outer wall and the outer skins of the flow altering structures, each flow altering structure outer skin forming a first portion of one of the cavities, each flow altering structure outer skin having at least one actuator connected thereto within the respective cavity, each actuator comprising;

a fixed pulling bracket coupled to an interior side of the nozzle body inner wall between the nozzle body inner and outer walls and within the cavity;

a free pulling bracket located between the nozzle body inner and outer walls and within the cavity, the free pulling bracket adapted to be movable within the cavity;

a control arm connected at a control arm first end to the free pulling bracket and at a control arm second end to a deployment cam linkage connected to the outer skin of the respective flow altering structure; and

a plurality of shape memory alloy (SMA) cables coupled at a SMA cable first end to the fixed pulling bracket and coupled at a SMA cable second end to the free pulling bracket, the SMA cables adapted to one-dimensionally constrict along a longitudinal center line of each respective SMA cable when activated, the constriction pulling the free pulling bracket and the control arm toward the fixed pulling bracket to thereby cause a lever plate of the deployment cam linkage to force the distal end of the appending structure inner skin to separate from the distal end of the appending structure outer skin and move appending structure inner skin from a first position to a second position.

27. The engine of claim 26, wherein each SMA cable comprises swaged fittings at the SMA cable first and second ends to couple each SMA cable the respective fixed pulling bracket and the free pulling bracket.

28. The engine of claim 26, wherein each SMA cable is electrically connected to an electrical current source whereby each SMA cable is activated by turning on the electrical current source such that current flows through the SMA cables.

29. The engine of claim 26, wherein the inner skin of each flow altering structure is adapted to act as a biasing component to return the flow altering structure inner skin to the first position when the SMA cables are deactivated.