Techniques to measure strain development and failure in a fabric
First Claim
1. A system for characterizing an impact in a fabric, said system comprising:
- a fabric comprising a plurality of individual yarns that have been woven into a plurality of layers wherein said fabric includes a sensing element woven in each of said layers to provide a plurality of sensing elements;
wherein a parameter of said plurality of sensing elements depends on a strain in said sensing element in each of said fabric layers;
a transducer coupled to each of said sensing element wherein said transducer is configured to generate an output voltage versus time including an initial linear slope region based on said parameter of said sensing, wherein said initial linear slope region is related to said strain according to the equation ε
=kwα
/2cfab, where ε
is said strain, kw is a wire constant associated with said sensing element, α
is said linear slope and cfab is the speed of sound in said fabric, and wherein said strain is a local strain such that said local strain is uniform over a portion of said sensing element; and
a controller coupled to said transducer, said controller configured to receive said output of said transducer, to determine a strain in said sensing element based, at least in part, on a change in said output voltage versus time of said transducer for each of said fabric layers, and to characterize said impact in said fabric based on said strain in said sensing element by determination of the location of said impact and failure of a layer indicated by a deviation from the linearity of said initial linear region of said voltage versus time slope.
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Abstract
The present disclosure relates to a system and method for characterizing an impact in a fabric. The system may include a sensing element woven in the fabric wherein a parameter of the sensing element depends on a strain in the sensing element; a transducer coupled to the sensing element wherein the transducer is configured to generate an output based on the parameter of the sensing element; and a controller coupled to the transducer, the controller configured to receive the output of the transducer, to determine a strain in the sensing element based, at least in part, on a change in the output of the transducer, and to characterize the impact in the fabric based on the strain in the sensing element.
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Citations
29 Claims
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1. A system for characterizing an impact in a fabric, said system comprising:
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a fabric comprising a plurality of individual yarns that have been woven into a plurality of layers wherein said fabric includes a sensing element woven in each of said layers to provide a plurality of sensing elements; wherein a parameter of said plurality of sensing elements depends on a strain in said sensing element in each of said fabric layers; a transducer coupled to each of said sensing element wherein said transducer is configured to generate an output voltage versus time including an initial linear slope region based on said parameter of said sensing, wherein said initial linear slope region is related to said strain according to the equation ε
=kwα
/2cfab, where ε
is said strain, kw is a wire constant associated with said sensing element, α
is said linear slope and cfab is the speed of sound in said fabric, and wherein said strain is a local strain such that said local strain is uniform over a portion of said sensing element; anda controller coupled to said transducer, said controller configured to receive said output of said transducer, to determine a strain in said sensing element based, at least in part, on a change in said output voltage versus time of said transducer for each of said fabric layers, and to characterize said impact in said fabric based on said strain in said sensing element by determination of the location of said impact and failure of a layer indicated by a deviation from the linearity of said initial linear region of said voltage versus time slope. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for characterizing an impact in a fabric, said method comprising:
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providing a fabric comprising a plurality of individual yarns that have been woven into a plurality of layers wherein said fabric includes a sensing element woven into each of said layers; monitoring an output, said output based on a parameter of said plurality of sensing elements wherein said parameter of said sensing element depends on a strain in said sensing element and said output comprises voltage versus time including an initial linear slope region, wherein said initial linear slope region is related to said strain according to the equation ε
=kwα
/2cfab, where ε
is said strain, kw is a wire constant associated with said sensing element, α
is said linear slope and cfab is the speed of sound in said fabric, and wherein said strain is a local strain such that said local strain is uniform over a portion of said sensing element;detecting a change in said output; determining said strain in said sensing element based on said change in said output; and characterizing said impact in said fabric based on said strain in said sensing element and determining the location of said impact and failure of a layer indicated by a deviation from the linearity of said initial portion of said voltage versus time slope. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. An article comprising a storage medium having stored thereon instructions that when executed by a machine result in the following operations:
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monitoring an output, said output based on a parameter of a sensing element wherein said sensing element is woven in a fabric comprising a plurality of individual yarns that have been woven into a plurality of layers wherein said fabric includes a sensing element woven in each of said layers and said parameter of said sensing element depends on a strain in said sensing element and said output comprises voltage versus time including an initial slope region, wherein said initial linear slope region is related to said strain according to the equation ε
=kwα
/2cfab, where ε
is said strain, kw is a wire constant associated with said sensing element, α
is said linear slope and cfab is the speed of sound in said fabric, and wherein said strain is a local strain such that said local strain is uniform over a portion of said sensing element;detecting a change in said output; determining said strain in said sensing element based on said change in said output; and characterizing an impact in said fabric based on said strain in said sensing element and determining the location of said impact and failure of a layer indicated by a deviation from the linearity of said initial portion of said voltage versus time slope. - View Dependent Claims (24, 25, 26, 27, 28, 29)
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Specification