ACTIVE MATERIAL INSERTS FOR USE WITH HOLLOW STRUCTURES

• US 20090066115A1
• Filed: 11/14/2008
• Published: 03/12/2009
• Est. Priority Date: 04/02/2004
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (General Motors Company)
• Inventors: BROWNE, ALAN L., JOHNSON, NANCY L.
• Granted Patent: US 8,256,829 B2
• Time in Patent Office: Days
• US Class Current: 296/187.30
• CPC Class Codes: B60R 19/40 in the direction of an obstacle before a collision , or extending during driving of the vehicle, i.e. to increase the energy absorption capacity of the bumper inflatable bumpers B60R19/20
• CPC Class Codes: B62D 21/15 having impact absorbing means, e.g. a frame designed to permanently or temporarily change shape or dimension upon impact with another body bumpers B60R19/02; shock absorbers in general F16F
• CPC Class Codes: B62D 29/00 Superstructures, understructures, or sub-units thereof, characterised by the material thereof B62D33/044, B62D33/048 take precedence
• CPC Class Codes: C21D 2201/01 Shape memory effect
• CPC Class Codes: C22F 1/006 Resulting in heat recoverable alloys with a memory effect

Abstract

A modifiable structural assembly comprising an active material based insert positioned within a hollow structural member, wherein the insert defines a first insert dimension, is configured, when activated, to change the first insert dimension to a second insert dimension, and selectively achieving the first or second dimension facilitates positioning the insert, or changes a characteristic of the assembly, such as the stiffness, damping effect, or energy absorption rate, once the insert has been positioned.

Claims

1. A modifiable structural assembly comprising:

a hollow structural member defining an interior opening; and

at least one insert securely positioned within the opening, and formed at least in part of an active material operable to selectively achieve first and second differing states when activated and deactivated respectively,

said member and at least one insert being cooperatively configured to present a first assembly characteristic value when the material is in the first state, and a second value when the material is in the second state.

2. The assembly claimed in claim 1, wherein the material is selected from the group consisting essentially of shape memory alloys, ferromagnetic shape memory alloys, shape memory polymers, magnetorheological elastomers, dielectric elastomers, ionic polymer metal compositions, electroactive polymers, and piezoelectric ceramics.

3. The assembly claimed in claim 1, wherein the member is a frame component of a vehicle, and the assembly characteristic value is the magnitude of energy absorption by the member during a crash event.

4. The assembly claimed in claim 3, wherein the material is passively activated by heat energy generated by or applied to the vehicle.

5. The assembly claimed in claim 1, wherein the opening defines a first internal dimension, and the insert when inserted and activated congruently defines a second dimension less than the first, and attempts to define a third dimension approximately equal to or greater than the first when inserted and deactivated, so as to variously create a mechanical interlock with interior geometrical features of or exert a force upon the member.

6. The assembly claimed in claim 5, wherein the second dimension is less than eighty-five percent of the first.

7. The assembly claimed in claim 1, wherein the opening defines a first internal dimension, and the insert when inserted and deactivated congruently defines a second dimension less than the first, and attempts to define a third dimension preferably greater than the first when inserted and activated, so as to exert a force upon the member.

8. The assembly claimed in claim 1, wherein the member further defines a non-linear longitudinal axis including at least one bend, and the insert when activated presents a malleable state, so as to enable the insert to be facilely bent within the bend, and a rigid state when deactivated, so as to create a mechanical interlock with and preferably increase the stiffness of the assembly.

9. The assembly claimed in claim 1, wherein the member further defines a non-linear opening and at least one bend, and the insert when deactivated presents a malleable state, so as to enable the insert to be facilely bent within the bend, and a rigid state when activated, so as to create a mechanical interlock with and preferably increase the stiffness of the assembly.

10. The assembly claimed in claim 1, wherein the insert presents a configuration selected from the group consisting essentially of “

I”

-beams, foams, lattices, trusses, hollow shells, and porous blocks.

11. The assembly claimed in claim 1, wherein the assembly characteristic values define a change in value, the material is activated and caused to achieve the first state by a magnetic field defining a strength, and the change in value is proportional to the strength.

12. The assembly claimed in claim 1, further comprising:

at least one sensor communicatively coupled to the insert, configured to determine an event, and operable to cause the material to be activated when the event is determined.

13. The assembly claimed in claim 12, further comprising:

a controller communicatively coupled to said at least one sensor and insert, configured to receive data from said at least one sensor, compare the data to a predetermined threshold, and cause the material to be activated only when the threshold is exceeded.

14. The assembly claimed in claim 12, wherein the member is a frame component of a vehicle, and the event is a collision.

15. An insert adapted for use with a hollow structural member defining opposite interior surfaces, wherein the surfaces contributively define an opening and an interior dimension, the insert defines a first insert dimension and comprises an active material element configured to change the first insert dimension to a second insert dimension, one of said first and second insert dimensions being less than the interior dimension so as to facilitate insertion into the opening, and the other of said first and second insert dimensions being greater than the interior dimension.

16. A method of modifying a structural assembly including a hollow structural member defining an opening, said method comprising the steps of:

a. securing the member so as to selectively engage a condition or event;

b. securing at least one insert within the opening, wherein the insert is formed at least in part of an active material operable to selectively achieve first and second differing states when activated and deactivated respectively; and

c. activating the material so as to achieve one of said first and second states, and modifying the assembly as a result of activating the material, when the condition or event is engaged.

17. The method claimed in claim 16, wherein the material is activated by an activation signal selected from the group consisting essentially of thermal heating, Joule heating, stress activation, applied magnetic field, and chemical activation.

18. The method claimed in claim 16, wherein the material is activated and caused to achieve said one of the first and second states by a magnetic field, and caused to achieve the other state by reversing the magnetic field.

19. The method claimed in claim 16, wherein steps a) and c) further include the steps of selectively engaging sound waves and/or structural vibrations, and modifying the damping rate of the assembly as a result of activating the material.

20. The method claimed in claim 16, wherein the assembly comprises a vehicle constructed during a manufacturing process having a paint curing component, and the material is activated and caused to achieve said one of the first and second states by the paint curing component.