Composite material used as a strain gauge

• US 10,658,567 B2
• Filed: 04/15/2019
• Issued: 05/19/2020
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Nano Composite Products, Inc.
• Original Assignee: Nano Composite Products, Inc.
• Inventors: Merrell, Aaron Jake, Fullwood, David T., Bowden, Anton E., Remington, Taylor D.
• Primary Examiner(s): Allen, Andre J
• Application Number:
  US16/384,609
• Publication Number:
  US 20190245134A1
• Time in Patent Office: 400 Days
• Field of Search: None
• CPC Class Codes: G01B 7/16 for measuring the deformation in a solid, e.g. by resistance strain gauge
• CPC Class Codes: G01L 1/16 using properties of piezoelectric devices
• CPC Class Codes: G01L 1/18 using properties of piezo-resistive materials, i.e. materials of which the ohmic resistance varies according to changes in magnitude or direction of force applied to the material
• CPC Class Codes: G01L 1/20 by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids of piezo-resistive materials G01L1/18; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
• CPC Class Codes: G01L 5/0052 measuring forces due to impact G01L5/0061, G01L5/14 take precedence; impact testing of structures G01M7/08; impact testing of material G01N3/00
• CPC Class Codes: H10N 30/092 Forming composite materials
• CPC Class Codes: H10N 30/852 Composite materials, e.g. having 1-3 or 2-2 type connectivity
• CPC Class Codes: Y10T 29/49117 Conductor or circuit manufacturing

Abstract

In one general aspect, an apparatus comprises a material including a non-layered mixture of an polymeric foam with a plurality of voids; and a plurality of conductive fillers disposed in the polymeric foam. The apparatus may produce an electrical response to deformation and, thus, function as a strain gauge. The electrical response may be a decrease in electrical resistance. The electrical response may be an electric potential generated. The conductive fillers may include conductive nanoparticles and/or conductive stabilizers. In another general aspect, a method of measuring compression strain includes detecting, along a first axis, an electrical response generated in response to an impact to a uniform composite material that includes conductive fillers and voids disposed throughout an elastomeric polymer, and determining a deformation of the impact based on the electrical response. The impact may be along a second axis different from the first axis.

Claims

1. A porous nanoparticle-polymer composite structure comprising:

a cured polymer;

conductive nanoparticles; and

conductive fibers,

wherein the nanoparticle-polymer composite structure is cured into a shape from a mixture including a curable liquid polymer, the conductive nanoparticles, and the conductive fibers.

2. The porous nanoparticle-polymer composite structure of claim 1, wherein the conductive fibers being up to 2.4% by weight of the porous nanoparticle-polymer composite structure.

3. The porous nanoparticle-polymer composite structure of claim 1, wherein the conductive fibers include carbon nanotubes.

4. The porous nanoparticle-polymer composite structure of claim 1, wherein the porous nanoparticle-polymer composite structure has a porosity with a value up to 80%.

5. The porous nanoparticle-polymer composite structure of claim 1, wherein the porous nanoparticle-polymer composite structure has an elastic modulus with a value matching an elastic modulus of an existing foam, wherein the porous nanoparticle-polymer composite structure replaces the existing foam in an object.

6. The porous nanoparticle-polymer composite structure of claim 1, wherein the porous nanoparticle-polymer composite structure produces an electrical response detectable along a first axis and along a second axis orthogonal to the first axis when deformed.

7. The porous nanoparticle-polymer composite structure of claim 1, wherein the porous nanoparticle-polymer composite structure has at least one probe disposed therein, the probe being connected to a voltage detector.

8. The porous nanoparticle-polymer composite structure of claim 1, wherein the porous nanoparticle-polymer composite structure generates a voltage in response to deformation without a current producing device.

9. A method for measuring compression strain comprising:

detecting, along a first axis, an electrical response generated in response to an impact to a porous nanoparticle-polymer composite structure comprising conductive fillers disposed throughout a cured polymer, the impact being along a second axis different from the first axis; and

determining a deformation of the impact based on the electrical response.

10. The method of claim 9, further comprising determining a strain rate and deformation for the impact based on the electrical response.

11. The method of claim 9, wherein the conductive fillers include conductive fibers and conductive nanoparticles.

12. The method of claim 9, where the porous nanoparticle-polymer composite structure functions as padding in a consumer apparatus.

13. The method of claim 9, wherein the electrical response is a voltage representing a decrease in electrical resistance or a voltage representing an electrical potential generated and the method further comprises:

transmitting data representing the voltage to an external computing device; and

determining the deformation of the impact at the external computing device based on the data.

14. The method of claim 9, wherein the porous nanoparticle-polymer composite structure is applied to a portion of an artificial limb, and the method further comprises providing feedback to a user about the deformation of the impact.

15. The method of claim 9, wherein the porous nanoparticle-polymer composite structure measures up to 80% strain without permanent deformation of the porous nanoparticle-polymer composite structure.

16. The method of claim 9, wherein the conductive fillers are dispersed in the cured polymer in an even manner from outer surface to outer surface.

17. The method of claim 9, wherein the electrical response includes a decrease in electrical resistance and an electric potential generated.

18. A porous polymer composite structure, comprising:

a uniform composite polymeric foam including conductive elements dispersed throughout the polymeric foam in an even manner from outer surface to outer surface, the conductive elements being up to 2.4% by weight of the porous polymer composite structure.

19. The porous polymer composite structure of claim 18, wherein, the conductive elements include conductive fibers.

20. The porous polymer composite structure of claim 18, wherein, the conductive elements are exclusively conductive fibers.

21. The porous polymer composite structure of claim 18, the conductive elements being up to 1.5% by weight of the porous polymer composite structure.

22. The porous polymer composite structure of claim 18, wherein the porous polymer composite structure generates, without a current producing device, electric potential in response to compression.