WO2003076953A2 - An electrical condition monitoring method for polymers - Google Patents

An electrical condition monitoring method for polymers Download PDF

Info

Publication number
WO2003076953A2
WO2003076953A2 PCT/US2003/006844 US0306844W WO03076953A2 WO 2003076953 A2 WO2003076953 A2 WO 2003076953A2 US 0306844 W US0306844 W US 0306844W WO 03076953 A2 WO03076953 A2 WO 03076953A2
Authority
WO
WIPO (PCT)
Prior art keywords
ofthe
conductive composite
polymer
electrical
degradation
Prior art date
Application number
PCT/US2003/006844
Other languages
French (fr)
Other versions
WO2003076953A3 (en
Inventor
Kenneth S. Watkins
Shelby J. Morris
Daniel D. Masakowski
Ching-Ping Wong
Shijian Luo
Original Assignee
Bpw, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Bpw, Inc. filed Critical Bpw, Inc.
Priority to AT03744208T priority Critical patent/ATE538373T1/en
Priority to AU2003225688A priority patent/AU2003225688A1/en
Priority to US10/506,518 priority patent/US7414416B2/en
Priority to EP03744208A priority patent/EP1490672B1/en
Publication of WO2003076953A2 publication Critical patent/WO2003076953A2/en
Publication of WO2003076953A3 publication Critical patent/WO2003076953A3/en
Priority to US12/082,161 priority patent/US7663381B2/en
Priority to US12/214,911 priority patent/US8829929B1/en

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
    • G01R31/1227—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
    • G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
    • G01N27/041—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/44—Resins; Plastics; Rubber; Leather
    • G01N33/445—Rubber
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N17/00—Investigating resistance of materials to the weather, to corrosion, or to light

Definitions

  • TITLE AN ELECTRICAL CONDITION MONITORING METHOD FOR POLYMERS
  • the present invention relates to methods and apparatus for determining deterioration and remaining life of polymeric material utilizing measured electrical quantities, and, more particularly, for determining mechanical properties and remaining life of a polymeric material by measurement of electrical resistivity of a conductive composite ofthe polymer.
  • the safe operation of existing and future plants such as nuclear power plants requires monitoring ofthe insulation materials in order to anticipate degradation before performance ofthe wire and cable is adversely affected.
  • Age related wire and cable failure is primarily a mechanical mechanism. As the insulation ages, it becomes embrittled and eventually fails mechanically by cracking and exposing bare conductors.
  • condition monitoring methods which monitor installed wire and cable and ensure that the materials have not degraded excessively. These methods are also used to predict safe operating lifetime of wire and cable insulation materials for anticipated environmental conditions.
  • CCM cable condition monitoring
  • Elongation-at-break has traditionally been one ofthe most common and well- documented CCM methods. This mechanical method measures the elongation of a sample of insulation material just prior to break and is normally expressed as a ratio ofthe break length divided by the original length ofthe sample. Since elongation measured in the test is analogous to elongation occurring when bending wire and cable, the results can be easily correlated to actual wire and cable insulation condition. Arrhenius methods described by others are normally used to predict material lifetime at a target ambient temperature from acceleration-aged data.
  • a serious disadvantage ofthe EAB method is that a relatively large sample portion is required to perform the test. This makes the test essentially destructive since the cable is rendered inoperative when the sample is removed. Even if a cable is sacrificed in order to run a test, some portions ofthe cable may be difficult or nearly impossible to access for sample removal, as would be the case if the area of interest is within a cable bundle, wire tray, or internal to a penetration. The equipment needed for measurement is relatively expensive and requires specialized skills.
  • Indenter modulus test is a relatively new mechanical test that utilizes a machine to press a small anvil at constant velocity against the outer surface ofthe cable or insulated conductor while measuring the force exerted on the anvil.
  • the indenter modulus is defined as the slope ofthe force-position curve.
  • a major advantage ofthe indenter modulus test is that the test itself is non-destructive. However, the test is of limited use on conductor insulation since access to a sufficient length of individual conductors is often restricted. Also, the test is not practical on cable within cable bundles or trays, or in other confined spaces.
  • Oxidation Induction Time is a chemical condition monitoring method that utilizes small (8-10 mg) samples removed from cable insulation materials.
  • the method utilizes a differential scanning calorimeter (DSC) to provide an indication of the rapid oxidation ofthe sample when anti-oxidants, normally present in the insulation material, are exhausted.
  • DSC differential scanning calorimeter
  • Short induction times indicate exhaustion ofthe anti-oxidant and anticipate rapid degradation ofthe material.
  • Sample collection requires access to the cable which limits testable portions ofthe cable. Measurement requires expensive laboratory equipment and specialized training.
  • Electrical condition monitoring methods include insulation resistance, high potential tests, tan-delta tests, and ionized gas medium tests. These tests are essentially "go-no- go" tests (do not predict the remaining life ofthe sample) since no well-established methods reliably predict insulation lifetime based on the results. Several of these tests require high electrical potentials to be connected to cables, requiring removal of connected equipment and loads in order for the tests to be performed.
  • an object ofthe present invention is to provide a condition monitoring method for polymers which provides the ability to measure an electrical property of a conductive composite ofthe polymer in a non-destructive manner.
  • Another object ofthe invention is to provide a condition monitoring method which allows correlation of an electrical property of a conductive composite ofthe polymer with a mechanical property.
  • the methodology ofthe proposed condition monitoring method utilizes the electrical resistivity of a conductive composite formed from a candidate polymer material as a highly sensitive measurement of a mechanical property (volume shrinkage). Volume shrinkage, in turn, will be correlated as a mechanical indicator of insulation material aging.
  • the method eliminates disadvantages of current methods and provides a condition monitoring method which improves safety and reduces condition monitoring costs.
  • inert conductive particles into the polymer to form a conductive composite provides several significant advantages for condition monitoring: (1) A small change in volume ofthe conductive composite results in a large change in electrical resistivity. A few percent change in volume fraction of the insulation material provides a potential of 3 - 5 orders of magnitude or more change in the resistivity ofthe composite. This high measurement sensitivity provides an opportunity to detect and monitor small aging effects which current condition monitoring methods are insensitive to; and
  • the conductive composite sensor may be distributed within a polymeric product such as electrical cables as a separate filament, or it could be co-extruded as a filament in the product.
  • FIGS. 1 A is a plot of elongation at break for a conductive composite sample of ethylene propylene rubber vs. age time at 125C.
  • FIG. IB is a plot of volume change (shrinkage) for a conductive composite sample of ethylene propylene rubber vs. age time at 125C.
  • FIG. 1C is a plot of density of a conductive composite sample of ethylene propylene rubber vs. age time at 125C.
  • FIG. 1 D is a plot of electrical resistivity of a conductive composite sample of ethylene propylene rubber vs. age time at 125C.
  • FIG. 2A is a cross section of an electrical cable comprising an age sensor filament made of a conductive composite
  • FIG. 2B is a cross section of an electrical cable comprising an age sensor filament co- extruded in an insulated conductor insulation and a cable jacket;
  • FIG. 3 is a schematic diagram of a means for measuring the resistivity of a conductive age sensor filament
  • FIG. 4 is a perspective drawing of an electrical cable comprising a plurality of age sensors disposed in the cable jacket;
  • FIG. 5 is a perspective drawing of an electrical cable comprising an age sensor strip disposed in the cable jacket;
  • FIG. 6 is a perspective drawing of a plurality of age sensor assemblies utilizing an RFID to communicate resistivity to an external instrument
  • FIG. 7 is a perspective drawing of a polymeric structure comprising a plurality of conductive composite age sensors disposed in the structure. Description ofthe Preferred Embodiments
  • resistivity electrical
  • conductivity as the reciprocal of resistivity, can be substituted as a measurable electrical property by those skilled in the art.
  • conductive composite polymer is generally meant to include any conductive composite comprising a mixture of conductive particles in a polymer matrix or base, and may include additional fillers, additives and binders.
  • This composite type conductive polymer is differentiated from intrinsically conductive polymers which posses electrically conductive properties without addition of conductive particles.
  • the method ofthe present invention utilizes measurement of an electrical property of a conductive composite to indirectly measure the aging or degradation effects on a polymeric material.
  • the conductive composite comprises conductive particles such as carbon black particles or metallic particles evenly dispersed or mixed in the polymeric material of interest. Degradation and aging effects which include chain scission and additional cross-linking will result in volumetric changes to the polymeric portion ofthe composite and will affect electrical properties such as the resistivity or conductivity ofthe composite.
  • Changes in the volume fraction of conductive fillers can be detected by electrical measurements ofthe conductive composite. Specifically, the resistivity (or conductivity) provides a measure ofthe volume fraction ofthe conductive filler.
  • Resistivity measurements of conductive composites affords very high sensitivity to conductive filler volume fraction changes in conductive polymer composites as a result of polymer matrix shrinkage and densification.
  • the volumetric shrinkage of a polymer due to age-related cross-linking may be on the order of only a few percent over the useful life ofthe polymer.
  • Selection ofthe conductive filler type and loading may result in several orders of magnitude of resistivity change due to the volumetric shrinkage. This is especially the case if the conductive filler loading is chosen to be in the percolation zone ofthe conductive composite.
  • Other aging mechanisms such as loss of volatile components ofthe polymer during aging also result in an increase in the volume fraction ofthe conductive filler.
  • the high sensitivity of resistivity of a conductive polymer composite to volumetric shrinkage (or expansion) ofthe polymer matrix provides an amplified method useful in detecting an measuring the small changes in polymer volume fraction as a result of age-related degradation such as cross-linking ofthe matrix due to thermal, radiation, and thermal oxidative mechanisms. While direct measurements of volumetric shrinkage ofthe polymers would provide a quantitative means to detect degradation, this method is usually destructive for many applications, and requires laboratory analysis. Measurement of resistivity, although an indirect measurement ofthe volumetric shrinkage, provides a non-destructive, in-situ, measurement that is much more sensitive than can be done by normal laboratory measurements of volumetric shrinkage or density, and can be carried out with simple field equipment such as an ohmmeter or multimeter.
  • the amplifying effect ofthe conductive composite resistivity measurement approach allows measurement of volumetric or density changes smaller than that afforded by direct mechanical measurements.
  • physical aging effects such as relaxation of polymer chain networks of polymers below the glass transition temperature, and creep effects can be detected over short time intervals by resistivity measurements of conductive composites ofthe polymer. Detection of natural aging effects over short time periods, such as days or weeks is possible by this method, where months or years would be required by conventional mechanical or chemical measurements such as elongation to break, and oxygen induction time (OIT) measurements.
  • OIT oxygen induction time
  • FIGS. 1 A, IB, and IC show elongation at break, volume change and density of ethylene propylene rubber (EPR) under accelerated thermal aging at 125C.
  • FIG. ID shows resistivity change for EPR samples under the same aging conditions.
  • resistivity data of polymeric composite materials could be used in several ways. For example, accelerated aging of a composite comprising a specific polymer and a given volume fraction of a conductive filler would result in a resistivity vs. time for the test temperature. Measurement of mechanical properties such as elongation at break or hardness as the composite is aged, would provide a relationship ofthe mechanical property to the resistivity for the composite. This relationship could be determined by the aging curves, such as that of FIGS. 1A, IB, IC and ID showing the value ofthe mechanical property vs. resistivity. Or, the relationship could be expressed by a mathematical algorithm by curve fitting methods known in the art. By inclusion of base polymer samples (without conductive fillers) during the aging trial, the mechanical properties ofthe base polymer could be predicted by measurement of a representative sample ofthe conductive composite having the same base polymer.
  • Arrhenius methodology and/or time/temperature superposition known in the art could be used to predict remaining lifetime ofthe composite (or base polymer) as a function of aging temperature.
  • In-situ measurement ofthe resistivity of a test or trial portion ofthe polymer having conductive filler could be used to verify the remaining life ofthe polymer and act as an indirect measurement of desired mechanical properties.
  • Physical aging affects of polymers could be modeled in a similar means by thermal processing a conductive composite, optionally in an inert gas environment, and measuring resistivity vs. mechanical properties such as volumetric shrinkage, density and creep properties.
  • FIG. 2A is a cross section of a multi-conductor cable 201 having three insulated conductors 203, an outer cable jacket 205, and an age sensor filament 207 disposed in the cabled conductors.
  • the age sensor filament "tracer" is a conductive composite comprising the conductor insulator polymer as the base polymer and conductive filler such as carbon black.
  • the conductive composite utilizes a second polymer as the base polymer.
  • the conductive composite utilizes metallic or metallic oxides as the conductive filler.
  • the sensor filament may be positioned at other locations in the cable such as outside the insulated conductors and inside the cable jacket.
  • Fig. 2B is an alternative embodiment 202 ofthe cable of FIG. 1 utilizing a co- extruded age sensor tracer 209 in the insulated portion ofthe insulated conductor, or an alternative age tracer 211 co-extruded in the cable jacket.
  • the base polymer ofthe senor tracers is the same polymer as the insulated conductor or jacket. In other embodiments, a different base polymer is utilized.
  • FIG. 3 is a schematic of a method of monitoring the resistivity ofthe age sensor 303 of cable 301.
  • Age sensor filament 303 is distributed along the cable and disposed, for example, along the insulated conductors 305.
  • a second element 303A is disposed along the length of cable 301 inside jacket 307.
  • Second element 303 A may be another age sensor filament similar to age sensor filament 303, or it may be an insulated or non-insulated conductor such as a metallic conductor.
  • Shunt 309 connects age sensor 303 and second element 303A to form a series-connected loop 311 which functions as an electrical age sensor for the cable.
  • Conductors 313 connect age sensor loop 311 to terminal box 315.
  • a resistance-measuring instrument such as ohmmeter 317 measures the resistance of age sensor loop 311 at terminal box 315. By monitoring resistance (or resistivity calculated from the sensor dimensions) changes in age sensor loop 311 and comparing the results to accelerated aged conductive composites and insulation base polymers, the material properties such as elongation-at-break ofthe insulation polymers may be determined.
  • ohmmeter 317 connects directly to age sensor 303 and second element 303A.
  • FIG. 4 is a perspective drawing of an alternative method of monitoring cable condition.
  • Cable 401 comprises a plurality of condition or age sensors 403 embedded in cable jacket 405.
  • Age sensors 403 may be a conductive composite of cable jacket 405 or insulated conductor 407 polymers co-extruded in jacket 405.
  • conductive composites utilized in age sensors 403 may be made of other polymers designed to degrade in a manner similar to insulated conductors 407 or jacket 405.
  • a composite condition or age sensing instrument such as ohmmeter 409 may comprise a probe 411 having terminals 413 spaced to provide a resistivity measurement of age sensors 403 when contacted with age sensor 403.
  • Terminals 413 comprise a predetermined spacing 415 to provide a resistivity reading of age sensors 403 which comprise a predetermined width 417 and predetermined thickness 419.
  • FIG. 5 is an alternative embodiment 501 ofthe cable of Fig 4 having a continuous condition/age sensor strip 503.
  • Sensor strip 503 comprises a predetermined width and thickness similar to age sensors 403 of FIG. 4.
  • FIG. 6 is an embodiment of another method of monitoring age sensors 603 of cable 601 by utilizing radio frequency identification (RFID) tag assemblies 605.
  • Tag assemblies 605 comprise age sensors 603 made from a conductive composite connected to an RFID chip 607.
  • RFID chip 607 may comprise an antenna 607A for active or passive communication with a reader 609.
  • a plurality of tag assemblies 605 may disposed in cable 601, for example by attaching assemblies 605 to tape 611 and wrapping tape 611 around insulated conductors 613.
  • Tape 611 may comprise an adhesive surface 615 for retaining tag assemblies 605.
  • a RFID tag assembly 605 may be connected to sensor loop 311 of cable 301 of FIG. 3 and embedded in cable 301.
  • FIG. 7 shows the method of FIG.
  • Age/condition sensors 703 are made from conductive composites as discussed in previous examples, and may be co-extruded, cast, or they may be applied as conductive hot-melt or adhesive composites. Continuous age sensor strips such as strip503 of FIG. 5 may be substituted for age sensors 703.
  • age sensor conductive composites utilize the base polymer ofthe structure they are monitoring, such as the insulation polymer for wire and cable age sensors, or PVC for house siding.
  • the age sensor composite may be "designed" to age at the same, or in some cases faster than the base polymer by altering the filler content, adding or deleting anti-oxidants to the age sensor, or "pre-aging" the age sensor by accelerated aging techniques to match aging performance with the polymeric structure being monitored. These techniques may also be used to alter the response ofthe age sensor to more nearly follow natural aging of the polymer.

Landscapes

  • Chemical & Material Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Electrochemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Food Science & Technology (AREA)
  • Medicinal Chemistry (AREA)
  • Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)

Abstract

An electrical condition monitoring method utilizes measurement of electrical resistivity of an age sensor (303) made of a conductive matrix or composite disposed in a polymeric structure such as an electrical cable (301). The conductive matrix comprises a base polymer and conductive filler. Cable (301) includes insulated conductors (305). Shunt (309) connects age sensor (303) with second element (303A) in a series connected age sensor loop (311). The method includes use of conductors (313) to connect age sensor loop (31) to terminal box (315) for communicating the resistivity to measuring instrument (317) and correlation of the resistivity of the conductive matrix of the polymeric structure with resistivity of an accelerated-aged conductive composite.

Description

Specification
Accompanying Application for Grant of U. S. Letters Patent
INVENTORS: Kenneth S. Watkins, Jr., Shelby J. Morris, Ching Ping Wong, Shijian
Luo, Daniel D. Masakowski ASSIGNEE: BPW, Inc.
TITLE: AN ELECTRICAL CONDITION MONITORING METHOD FOR POLYMERS
This application resulted, in part, from research funded by the U. S. Department of Energy. Certain rights for any intellectual property resulting from this application may apply to the Government ofthe United States. This application claims priority for United States Provisional Application No. 60/362,157 filed 03/06/2002.
Field of the Invention
The present invention relates to methods and apparatus for determining deterioration and remaining life of polymeric material utilizing measured electrical quantities, and, more particularly, for determining mechanical properties and remaining life of a polymeric material by measurement of electrical resistivity of a conductive composite ofthe polymer.
Background of the Invention
The polymeric materials used in wire and cable insulation and jacketing (and other polymers) degrade with age, especially in severe environmental conditions. The safe operation of existing and future plants such as nuclear power plants requires monitoring ofthe insulation materials in order to anticipate degradation before performance ofthe wire and cable is adversely affected. Age related wire and cable failure is primarily a mechanical mechanism. As the insulation ages, it becomes embrittled and eventually fails mechanically by cracking and exposing bare conductors. The industry has spent considerable time and effort to develop condition monitoring methods which monitor installed wire and cable and ensure that the materials have not degraded excessively. These methods are also used to predict safe operating lifetime of wire and cable insulation materials for anticipated environmental conditions. Presently, cable condition monitoring (CCM) methods are categorized as mechanical methods, chemical methods and electrical methods.
Elongation-at-break (EAB) has traditionally been one ofthe most common and well- documented CCM methods. This mechanical method measures the elongation of a sample of insulation material just prior to break and is normally expressed as a ratio ofthe break length divided by the original length ofthe sample. Since elongation measured in the test is analogous to elongation occurring when bending wire and cable, the results can be easily correlated to actual wire and cable insulation condition. Arrhenius methods described by others are normally used to predict material lifetime at a target ambient temperature from acceleration-aged data.
A serious disadvantage ofthe EAB method is that a relatively large sample portion is required to perform the test. This makes the test essentially destructive since the cable is rendered inoperative when the sample is removed. Even if a cable is sacrificed in order to run a test, some portions ofthe cable may be difficult or nearly impossible to access for sample removal, as would be the case if the area of interest is within a cable bundle, wire tray, or internal to a penetration. The equipment needed for measurement is relatively expensive and requires specialized skills.
Indenter modulus test is a relatively new mechanical test that utilizes a machine to press a small anvil at constant velocity against the outer surface ofthe cable or insulated conductor while measuring the force exerted on the anvil. The indenter modulus is defined as the slope ofthe force-position curve. A major advantage ofthe indenter modulus test is that the test itself is non-destructive. However, the test is of limited use on conductor insulation since access to a sufficient length of individual conductors is often restricted. Also, the test is not practical on cable within cable bundles or trays, or in other confined spaces.
Oxidation Induction Time (OIT) is a chemical condition monitoring method that utilizes small (8-10 mg) samples removed from cable insulation materials. The method utilizes a differential scanning calorimeter (DSC) to provide an indication of the rapid oxidation ofthe sample when anti-oxidants, normally present in the insulation material, are exhausted. Short induction times indicate exhaustion ofthe anti-oxidant and anticipate rapid degradation ofthe material. Sample collection requires access to the cable which limits testable portions ofthe cable. Measurement requires expensive laboratory equipment and specialized training.
Electrical condition monitoring methods include insulation resistance, high potential tests, tan-delta tests, and ionized gas medium tests. These tests are essentially "go-no- go" tests (do not predict the remaining life ofthe sample) since no well-established methods reliably predict insulation lifetime based on the results. Several of these tests require high electrical potentials to be connected to cables, requiring removal of connected equipment and loads in order for the tests to be performed.
Summary of the Invention
Therefore an object ofthe present invention is to provide a condition monitoring method for polymers which provides the ability to measure an electrical property of a conductive composite ofthe polymer in a non-destructive manner.
Another object ofthe invention is to provide a condition monitoring method which allows correlation of an electrical property of a conductive composite ofthe polymer with a mechanical property.
Another object ofthe invention is to provide a condition monitoring method which allows correlation of an electrical property of a conductive composite ofthe polymer with remaining life ofthe polymer. Still another object ofthe invention is to provide a condition monitoring method which utilizes a conductive polymer tracer to monitor the aging conditions in any environment.
The methodology ofthe proposed condition monitoring method utilizes the electrical resistivity of a conductive composite formed from a candidate polymer material as a highly sensitive measurement of a mechanical property (volume shrinkage). Volume shrinkage, in turn, will be correlated as a mechanical indicator of insulation material aging. The method eliminates disadvantages of current methods and provides a condition monitoring method which improves safety and reduces condition monitoring costs.
The incorporation of inert conductive particles into the polymer to form a conductive composite provides several significant advantages for condition monitoring: (1) A small change in volume ofthe conductive composite results in a large change in electrical resistivity. A few percent change in volume fraction of the insulation material provides a potential of 3 - 5 orders of magnitude or more change in the resistivity ofthe composite. This high measurement sensitivity provides an opportunity to detect and monitor small aging effects which current condition monitoring methods are insensitive to; and
(2) Measurement ofthe electrical resistivity is a simple measurement requiring no special equipment, expertise or removal from service.
The conductive composite sensor may be distributed within a polymeric product such as electrical cables as a separate filament, or it could be co-extruded as a filament in the product.
Brief Description of the Drawings
These and other features, aspects and advantages ofthe present invention will become better understood with regard to the following description, appended claims and accompanying drawings where: FIGS. 1 A is a plot of elongation at break for a conductive composite sample of ethylene propylene rubber vs. age time at 125C.
FIG. IB is a plot of volume change (shrinkage) for a conductive composite sample of ethylene propylene rubber vs. age time at 125C.
FIG. 1C is a plot of density of a conductive composite sample of ethylene propylene rubber vs. age time at 125C.
FIG. 1 D is a plot of electrical resistivity of a conductive composite sample of ethylene propylene rubber vs. age time at 125C.
FIG. 2A is a cross section of an electrical cable comprising an age sensor filament made of a conductive composite;
FIG. 2B is a cross section of an electrical cable comprising an age sensor filament co- extruded in an insulated conductor insulation and a cable jacket;
FIG. 3 is a schematic diagram of a means for measuring the resistivity of a conductive age sensor filament;
FIG. 4 is a perspective drawing of an electrical cable comprising a plurality of age sensors disposed in the cable jacket;
FIG. 5 is a perspective drawing of an electrical cable comprising an age sensor strip disposed in the cable jacket;
FIG. 6 is a perspective drawing of a plurality of age sensor assemblies utilizing an RFID to communicate resistivity to an external instrument; and
FIG. 7 is a perspective drawing of a polymeric structure comprising a plurality of conductive composite age sensors disposed in the structure. Description ofthe Preferred Embodiments
The following is a description ofthe preferred embodiments of a method for determining the degradation of a polymeric material by use of an electrical measurement.
Definitions: Although the term resistivity (electrical) is used throughout the specification, it is understood that conductivity, as the reciprocal of resistivity, can be substituted as a measurable electrical property by those skilled in the art.
The term conductive composite polymer, as used in this specification, is generally meant to include any conductive composite comprising a mixture of conductive particles in a polymer matrix or base, and may include additional fillers, additives and binders. This composite type conductive polymer is differentiated from intrinsically conductive polymers which posses electrically conductive properties without addition of conductive particles.
The method ofthe present invention utilizes measurement of an electrical property of a conductive composite to indirectly measure the aging or degradation effects on a polymeric material. In the preferred embodiments, the conductive composite comprises conductive particles such as carbon black particles or metallic particles evenly dispersed or mixed in the polymeric material of interest. Degradation and aging effects which include chain scission and additional cross-linking will result in volumetric changes to the polymeric portion ofthe composite and will affect electrical properties such as the resistivity or conductivity ofthe composite.
Degradation and aging mechanisms of polymers are numerous and complex, but cross-linking of polymer chains, caused by thermal exposure, radiation exposure, and thermal-oxidative mechanisms has been shown in the literature to result in increased packing density ofthe polymer chains, resulting in densification and volumetric shrinkage. If conductive fillers are chosen which are relatively inert for the environments in which the composites are used and tested, the volume fraction ofthe filler will remain constant with degradation ofthe polymer matrix. The resulting volumetric shrinkage of the polymer matrix of a conductive composite results in an increase in the volume fraction ofthe conductive filler particles in the composite.
Changes in the volume fraction of conductive fillers can be detected by electrical measurements ofthe conductive composite. Specifically, the resistivity (or conductivity) provides a measure ofthe volume fraction ofthe conductive filler.
Resistivity measurements of conductive composites affords very high sensitivity to conductive filler volume fraction changes in conductive polymer composites as a result of polymer matrix shrinkage and densification. For example, the volumetric shrinkage of a polymer due to age-related cross-linking may be on the order of only a few percent over the useful life ofthe polymer. Selection ofthe conductive filler type and loading may result in several orders of magnitude of resistivity change due to the volumetric shrinkage. This is especially the case if the conductive filler loading is chosen to be in the percolation zone ofthe conductive composite. Other aging mechanisms, such as loss of volatile components ofthe polymer during aging also result in an increase in the volume fraction ofthe conductive filler.
The high sensitivity of resistivity of a conductive polymer composite to volumetric shrinkage (or expansion) ofthe polymer matrix provides an amplified method useful in detecting an measuring the small changes in polymer volume fraction as a result of age-related degradation such as cross-linking ofthe matrix due to thermal, radiation, and thermal oxidative mechanisms. While direct measurements of volumetric shrinkage ofthe polymers would provide a quantitative means to detect degradation, this method is usually destructive for many applications, and requires laboratory analysis. Measurement of resistivity, although an indirect measurement ofthe volumetric shrinkage, provides a non-destructive, in-situ, measurement that is much more sensitive than can be done by normal laboratory measurements of volumetric shrinkage or density, and can be carried out with simple field equipment such as an ohmmeter or multimeter.
The amplifying effect ofthe conductive composite resistivity measurement approach allows measurement of volumetric or density changes smaller than that afforded by direct mechanical measurements. For example physical aging effects, such as relaxation of polymer chain networks of polymers below the glass transition temperature, and creep effects can be detected over short time intervals by resistivity measurements of conductive composites ofthe polymer. Detection of natural aging effects over short time periods, such as days or weeks is possible by this method, where months or years would be required by conventional mechanical or chemical measurements such as elongation to break, and oxygen induction time (OIT) measurements.
Examples: FIGS. 1 A, IB, and IC show elongation at break, volume change and density of ethylene propylene rubber (EPR) under accelerated thermal aging at 125C. FIG. ID shows resistivity change for EPR samples under the same aging conditions.
Use of resistivity data of polymeric composite materials could be used in several ways. For example, accelerated aging of a composite comprising a specific polymer and a given volume fraction of a conductive filler would result in a resistivity vs. time for the test temperature. Measurement of mechanical properties such as elongation at break or hardness as the composite is aged, would provide a relationship ofthe mechanical property to the resistivity for the composite. This relationship could be determined by the aging curves, such as that of FIGS. 1A, IB, IC and ID showing the value ofthe mechanical property vs. resistivity. Or, the relationship could be expressed by a mathematical algorithm by curve fitting methods known in the art. By inclusion of base polymer samples (without conductive fillers) during the aging trial, the mechanical properties ofthe base polymer could be predicted by measurement of a representative sample ofthe conductive composite having the same base polymer.
By incorporating aging trials of a conductive composite at several temperatures, measuring resistivity and mechanical properties vs. aging time, Arrhenius methodology and/or time/temperature superposition known in the art could be used to predict remaining lifetime ofthe composite (or base polymer) as a function of aging temperature. In-situ measurement ofthe resistivity of a test or trial portion ofthe polymer having conductive filler could be used to verify the remaining life ofthe polymer and act as an indirect measurement of desired mechanical properties. Physical aging affects of polymers could be modeled in a similar means by thermal processing a conductive composite, optionally in an inert gas environment, and measuring resistivity vs. mechanical properties such as volumetric shrinkage, density and creep properties.
FIG. 2A is a cross section of a multi-conductor cable 201 having three insulated conductors 203, an outer cable jacket 205, and an age sensor filament 207 disposed in the cabled conductors. In the preferred embodiments, the age sensor filament "tracer" is a conductive composite comprising the conductor insulator polymer as the base polymer and conductive filler such as carbon black. In other embodiments, the conductive composite utilizes a second polymer as the base polymer. In still other embodiments, the conductive composite utilizes metallic or metallic oxides as the conductive filler. The sensor filament may be positioned at other locations in the cable such as outside the insulated conductors and inside the cable jacket.
Fig. 2B is an alternative embodiment 202 ofthe cable of FIG. 1 utilizing a co- extruded age sensor tracer 209 in the insulated portion ofthe insulated conductor, or an alternative age tracer 211 co-extruded in the cable jacket. In the preferred embodiments, the base polymer ofthe senor tracers is the same polymer as the insulated conductor or jacket. In other embodiments, a different base polymer is utilized.
FIG. 3 is a schematic of a method of monitoring the resistivity ofthe age sensor 303 of cable 301. Age sensor filament 303 is distributed along the cable and disposed, for example, along the insulated conductors 305. A second element 303A, is disposed along the length of cable 301 inside jacket 307. Second element 303 A may be another age sensor filament similar to age sensor filament 303, or it may be an insulated or non-insulated conductor such as a metallic conductor. Shunt 309 connects age sensor 303 and second element 303A to form a series-connected loop 311 which functions as an electrical age sensor for the cable. Conductors 313 connect age sensor loop 311 to terminal box 315. A resistance-measuring instrument, such as ohmmeter 317 measures the resistance of age sensor loop 311 at terminal box 315. By monitoring resistance (or resistivity calculated from the sensor dimensions) changes in age sensor loop 311 and comparing the results to accelerated aged conductive composites and insulation base polymers, the material properties such as elongation-at-break ofthe insulation polymers may be determined.
In other embodiments ohmmeter 317 connects directly to age sensor 303 and second element 303A.
FIG. 4 is a perspective drawing of an alternative method of monitoring cable condition. Cable 401 comprises a plurality of condition or age sensors 403 embedded in cable jacket 405. Age sensors 403 may be a conductive composite of cable jacket 405 or insulated conductor 407 polymers co-extruded in jacket 405. In other embodiments, conductive composites utilized in age sensors 403 may be made of other polymers designed to degrade in a manner similar to insulated conductors 407 or jacket 405.
A composite condition or age sensing instrument such as ohmmeter 409 may comprise a probe 411 having terminals 413 spaced to provide a resistivity measurement of age sensors 403 when contacted with age sensor 403. Terminals 413 comprise a predetermined spacing 415 to provide a resistivity reading of age sensors 403 which comprise a predetermined width 417 and predetermined thickness 419.
FIG. 5 is an alternative embodiment 501 ofthe cable of Fig 4 having a continuous condition/age sensor strip 503. Sensor strip 503 comprises a predetermined width and thickness similar to age sensors 403 of FIG. 4.
FIG. 6 is an embodiment of another method of monitoring age sensors 603 of cable 601 by utilizing radio frequency identification (RFID) tag assemblies 605. Tag assemblies 605 comprise age sensors 603 made from a conductive composite connected to an RFID chip 607. RFID chip 607 may comprise an antenna 607A for active or passive communication with a reader 609. A plurality of tag assemblies 605 may disposed in cable 601, for example by attaching assemblies 605 to tape 611 and wrapping tape 611 around insulated conductors 613. Tape 611 may comprise an adhesive surface 615 for retaining tag assemblies 605. In still other embodiments, a RFID tag assembly 605 may be connected to sensor loop 311 of cable 301 of FIG. 3 and embedded in cable 301. FIG. 7 shows the method of FIG. 4 applied to other extruded or cast polymer products 701 such as extruded or cast polymer siding, extruded or cast polymer pipe or tube, extruded, cast or laid-up composite structures such as aircraft structural parts and boat hulls. Age/condition sensors 703 are made from conductive composites as discussed in previous examples, and may be co-extruded, cast, or they may be applied as conductive hot-melt or adhesive composites. Continuous age sensor strips such as strip503 of FIG. 5 may be substituted for age sensors 703.
In the preferred embodiments, age sensor conductive composites utilize the base polymer ofthe structure they are monitoring, such as the insulation polymer for wire and cable age sensors, or PVC for house siding. In some embodiments, the age sensor composite may be "designed" to age at the same, or in some cases faster than the base polymer by altering the filler content, adding or deleting anti-oxidants to the age sensor, or "pre-aging" the age sensor by accelerated aging techniques to match aging performance with the polymeric structure being monitored. These techniques may also be used to alter the response ofthe age sensor to more nearly follow natural aging of the polymer.
Although the description above contains many specifications, these should not be construed as limiting the scope ofthe invention but merely providing illustrations of some ofthe presently preferred embodiments of this invention. Thus the scope ofthe invention should be determined by the appended claims and their legal equivalents, rather than by the examples given.

Claims

ClaimsWe Claim:
1. A method of determining degradation of a polymer, the method comprising the steps of: adding conductive particles to the polymer to form a conductive composite comprising a preselected weight percent of conductive particles; making an electrical connection with the conductive composite and measuring an electrical property ofthe conductive composite; and equating the measured electrical property ofthe conductive composite with the electrical property of a previously-degraded sample ofthe conductive composite to determine the degradation ofthe polymer.
2. The method of claim 1 wherein the measured electrical property is electrical resistivity.
3. The method of claim 1 wherein the measured electrical property is electrical conductivity.
4. The method of claim 1 wherein the degradation ofthe polymer is mechanical degradation ofthe polymer.
5. The method of claim 4 wherein the mechanical property comprises a durometer ofthe polymer.
6. The method of claim 4 wherein the mechanical property comprises an elongation property ofthe polymer.
7. The method of claim 4 wherein the mechanical property comprises a hardness ofthe polymer.
8. The method of claim 4 wherein the mechanical property comprises a tensile strength of the polymer.
9. The method of claim 4 wherein the mechanical property comprises a toughness ofthe polymer.
10. The method of claim 1 wherein the degradation ofthe polymer is a chemical degradation.
11. The method of claim 10 wherein the chemical degradation comprises a measure of oxidation ofthe polymer.
12. The method of claim 10 wherein the chemical degradation comprises a measure of a remaining amount of anti-oxidant added to the polymer.
13. The method of claim 1 wherein the previously degraded sample was degraded by an accelerated aging means.
14. The method of claim 13 wherein the accelerated aging means comprises aging in an environment elevated in temperature as compared to the normal operating temperature of the polymer.
15. The method of claim 13 wherein the accelerated aging means comprises aging in an elevated radiation environment.
16. The method of claim 13 wherein the accelerated aging means comprises aging in an elevated humidity environment.
17. A degradation sensor for a polymeric structure, the sensor comprising: a first quantity of conductive particles dispersed in a first portion ofthe polymeric structure to define a conductive composite portion, the first portion comprising less than a total polymer in the structure; and a means for communicating an electrical measurement ofthe conductive composite to an electrical measurement apparatus.
18. The degradation sensor of claim 17 wherein the means for communicating an electrical measurement ofthe conductive composite comprises a portion ofthe conductive composite disposed on an outside surface ofthe polymeric structure.
19. The degradation sensor of claim 17 wherein the means for communicating an electrical measurement ofthe conductive composite comprises a metallic conductor communicating with the conductive composite.
20. The degradation sensor of claim 17 wherein the means for communicating an electrical measurement ofthe conductive composite comprises an electromagnetic emitter.
21. The degradation sensor of claim 20 wherein the electromagnetic emitter is a radio frequency identification tag.
22. The degradation sensor of claim 17 wherein the conductive composite defines a filament disposed in the polymeric structure.
23. The degradation sensor of claim 17 wherein the conductive composite defines an extruded strip in the polymeric structure.
24. The degradation sensor of claim 17 wherein the conductive composite defines a plurality of portions of conductive composite, said plurality of portions of conductive composite being separated from each other by portions of polymer without said conductive particles.
25. A polymeric structure comprising: a degradation sensor for the polymeric structure, the sensor comprising: a first quantity of conductive particles dispersed in a first portion ofthe polymeric structure to define a conductive composite portion, the first portion comprising less than a total polymer in the structure; and a means for communicating an electrical measurement ofthe conductive composite to an electrical measurement apparatus.
26. The polymeric structure of claim 25 wherein the polymeric structure is the insulation of an electrical wire.
27. The polymeric structure of claim 25 wherein the polymeric structure is an electrical cable.
28. The polymeric structure of claim 25 wherein the polymeric structure is a pipe.
29. The polymeric structure of claim 25 wherein the polymeric structure is a building siding portion.
30. The polymeric structure of claim 25 wherein the polymeric structure is an aircraft composite structure.
31. The polymeric structure of claim 25 wherein the polymeric structure is a boat hull.
32. A method of determining degradation of a first polymer, the method comprising the steps of: adding conductive particles to a second polymer to form a conductive composite comprising a preselected weight percent of conductive particles; making an electrical connection with the conductive composite and measuring an electrical property ofthe conductive composite; and equating the measured electrical property ofthe conductive composite with the electrical property of a previously-degraded sample ofthe conductive composite to determine the degradation ofthe first polymer.
33. The method of claim 32 wherein the measured electrical property is electrical resistivity.
33. The method of claim 32 wherein the measured electrical property is electrical conductivity.
34. The method of claim 32 wherein the degradation ofthe first polymer is a mechanical degradation.
35. The method of claim 34 wherein the mechanical degradation is a degradation of a mechanical property selected from the group of a strength property, a hardness property, a density property, a dimensional property, and an elongation property.
36. A condition-sensing electrical cable comprising a combination of: an insulation component made of a first polymeric material; and an age sensor comprising a first quantity of conductive particles dispersed in a second polymeric material to define a conductive composite portion disposed within the cable, and; a means for communicating an electrical measurement ofthe conductive composite portion to an electrical measurement apparatus.
37. A condition-sensing building component comprising a combination of: a structural portion made of a first polymeric material; and an age sensor comprising a first quantity of conductive particles dispersed in a second polymeric material to define a conductive composite portion disposed in proximity to the structural portion, and; a means for communicating an electrical measurement ofthe conductive composite portion to an electrical measurement apparatus.
38. A condition-sensing vehicle comprising a combination of: a structural component made of a first polymeric material; and an age sensor comprising a first quantity of conductive particles dispersed in a second polymeric material to define a conductive composite portion disposed in proximity to the structural component, and; a means for communicating an electrical measurement ofthe conductive composite portion to an electrical measurement apparatus.
PCT/US2003/006844 2002-03-06 2003-03-05 An electrical condition monitoring method for polymers WO2003076953A2 (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
AT03744208T ATE538373T1 (en) 2002-03-06 2003-03-05 ELECTRICAL MONITORING METHOD FOR POLYMERS
AU2003225688A AU2003225688A1 (en) 2002-03-06 2003-03-05 An electrical condition monitoring method for polymers
US10/506,518 US7414416B2 (en) 2002-03-06 2003-03-05 Electrical condition monitoring method for polymers
EP03744208A EP1490672B1 (en) 2002-03-06 2003-03-05 An electrical condition monitoring method for polymers
US12/082,161 US7663381B2 (en) 2002-03-06 2008-04-09 Electrical condition monitoring method for polymers
US12/214,911 US8829929B1 (en) 2002-03-06 2008-06-24 Method and apparatus for measuring degradation of rubber products

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US36215702P 2002-03-06 2002-03-06
US60/362,157 2002-03-06

Related Child Applications (3)

Application Number Title Priority Date Filing Date
US10506518 A-371-Of-International 2003-03-05
US12/082,161 Division US7663381B2 (en) 2002-03-06 2008-04-09 Electrical condition monitoring method for polymers
US12/214,911 Continuation-In-Part US8829929B1 (en) 2002-03-06 2008-06-24 Method and apparatus for measuring degradation of rubber products

Publications (2)

Publication Number Publication Date
WO2003076953A2 true WO2003076953A2 (en) 2003-09-18
WO2003076953A3 WO2003076953A3 (en) 2004-05-27

Family

ID=27805136

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2003/006844 WO2003076953A2 (en) 2002-03-06 2003-03-05 An electrical condition monitoring method for polymers

Country Status (5)

Country Link
US (2) US7414416B2 (en)
EP (1) EP1490672B1 (en)
AT (1) ATE538373T1 (en)
AU (1) AU2003225688A1 (en)
WO (1) WO2003076953A2 (en)

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2005081930A2 (en) 2004-02-24 2005-09-09 Polymer Aging Concepts, Inc. Heath monitoring method and apparatus for composite materials
US7382263B2 (en) 2005-05-20 2008-06-03 Dow Global Technologies Inc. Oral drug compliance monitoring using radio frequency identification tags
WO2009003853A2 (en) 2007-07-02 2009-01-08 Contitech Ag Expansion sensor and corresponding sensor arrangement
US7612325B1 (en) 2007-08-22 2009-11-03 Watkins Jr Kenneth S Electrical sensor for monitoring degradation of products from environmental stressors
US7659728B1 (en) 2006-08-23 2010-02-09 Watkins Jr Kenneth S Method and apparatus for measuring degradation of insulation of electrical power system devices
US7924031B2 (en) 2005-02-23 2011-04-12 Watkins Jr Kenneth S Health monitoring method for composite materials
WO2012026993A1 (en) * 2010-08-26 2012-03-01 The Boeing Company Automated tire inspections utilizing conductive filaments
US8812251B2 (en) 2011-04-12 2014-08-19 The Boeing Company System and method for monitoring bonding integrity
PT106994A (en) * 2013-06-09 2014-12-09 Active Space Technologies Actividades Aeroespaciais Lda METHOD AND MONITORING SYSTEM FOR AGING ELECTRIC WIRING
US9002661B2 (en) 2010-08-26 2015-04-07 The Boeing Company Automated tire inspections utilizing fluorescing nano-particles
CN104713818A (en) * 2013-12-17 2015-06-17 甘肃金海新材料有限公司 Replacement and maintenance method for sand prevention net and sand prevention net evaluation method
US9267906B2 (en) 2011-04-12 2016-02-23 The Boeing Company Bondline embedded current sensor
US9567104B2 (en) 2011-04-12 2017-02-14 The Boeing Company Utilization of aircraft bondline embedded current sensors in the determination of a lightning damage index
RU193046U1 (en) * 2019-07-10 2019-10-11 федеральное государственное автономное образовательное учреждение высшего образования "Санкт-Петербургский политехнический университет Петра Великого" (ФГАОУ ВО "СПбПУ") Coaxial cylindrical electrode system for measuring the frequency dependence of the conductivity of composite materials
US11865931B2 (en) 2018-10-17 2024-01-09 Robert Bosch Gmbh Line set for a charging station, charging station

Families Citing this family (25)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7514941B2 (en) * 2006-03-15 2009-04-07 Raytheon Company Method and apparatus for predicting the reliability of electronic systems
US20070276627A1 (en) * 2006-05-25 2007-11-29 Westerman Everett A Repair determination for heat damaged composite structures
US8217669B1 (en) * 2007-08-22 2012-07-10 Watkins Jr Kenneth S Electrical sensor for monitoring degradation of products from environmental stressors
US7705615B2 (en) * 2007-09-14 2010-04-27 Strattec Power Access Llc Extruded capacitive sensor assembly and detection method
US7977952B2 (en) * 2007-12-21 2011-07-12 Gary Krutz Polymeric structures and methods for producing and monitoring polymeric structures
JP2009174899A (en) * 2008-01-22 2009-08-06 Hitachi Cable Ltd Cable type load sensor
JP5233292B2 (en) * 2008-01-23 2013-07-10 日立電線株式会社 Cable type load sensor
US8264347B2 (en) * 2008-06-24 2012-09-11 Trelleborg Sealing Solutions Us, Inc. Seal system in situ lifetime measurement
CN102124319A (en) * 2008-08-20 2011-07-13 纳幕尔杜邦公司 Method for evaluating high temperature wear life
US8752438B2 (en) * 2009-01-16 2014-06-17 The Board Of Regents Of The University Of Oklahoma Sensor-enabled geosynthetic material and method of making and using the same
US7975556B2 (en) * 2009-01-16 2011-07-12 The Board Of Regents Of The University Of Oklahoma Sensor-enabled geosynthetic material and method of making and using the same
KR101161776B1 (en) 2010-09-03 2012-07-03 한국전력공사 Device and method of degradation diagnosis for power cable
WO2012054710A1 (en) * 2010-10-22 2012-04-26 Celgard Llc Testing and measuring devices, systems, components and methods
EP2757364B1 (en) 2013-01-17 2018-12-26 Nexans Use of a polymer mixture as sensing mixture
TW201504637A (en) 2013-07-23 2015-02-01 Iner Aec Executive Yuan Method for evaluating cable aging and deterioration by using slice sampling
CN103728239B (en) * 2014-01-02 2015-11-04 国家电网公司 A kind of contactless coating failure detection system and detection method
WO2016053933A1 (en) 2014-09-29 2016-04-07 Avery Dennison Corporation Tire tracking rfid label
US9779351B1 (en) 2016-02-29 2017-10-03 Brunswick Corporation Marine vessel hull with embedded wireless identification device
DE102016213157A1 (en) * 2016-07-19 2018-01-25 Contitech Mgw Gmbh Test method for determining the aging of polymeric hollow bodies
US11221616B2 (en) * 2017-06-27 2022-01-11 Schneider Electric Systems Usa, Inc. Sensor service prediction
US11016051B1 (en) 2017-10-25 2021-05-25 Materials Technology Institute, Inc. (MTI) Wireless sensors for use in polymers to measure the structural integrity of the same and methods of manufacture thereof
CN110108983B (en) * 2019-05-23 2020-03-20 深圳市壹电电力技术有限公司 Intelligent cable state online measurement and control management method
CN110455698B (en) * 2019-08-01 2022-03-18 复旦大学 Comprehensive method for quantitatively evaluating ageing degree of nuclear-grade cable
CN111366824A (en) * 2020-04-10 2020-07-03 国网浙江省电力有限公司电力科学研究院 Aging sensor based on conductive composite material and manufacturing method thereof
EP3933369B1 (en) * 2020-07-03 2023-11-22 Lapp Engineering AG Cable

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4520341A (en) * 1981-12-08 1985-05-28 Sharp Kabushiki Kaisha Moisture responsive element with crosslinked organic membrane and protective layering
US4988875A (en) * 1988-12-13 1991-01-29 At&T Bell Laboratories Near infrared polyethylene inspection system and method
US5789665A (en) * 1996-04-25 1998-08-04 Voelker Sensors, Inc. Oil quality sensor for use in a motor

Family Cites Families (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3603142A (en) * 1970-05-07 1971-09-07 Donald Saylak Method of detecting cracks and measuring strain in polymeric structures
US4675662A (en) 1984-08-06 1987-06-23 Nippon Soken, Inc. Machine oil deterioration detection
JPS6144339A (en) * 1984-08-07 1986-03-04 Nippon Soken Inc Oil deterioration detector
US4631952A (en) * 1985-08-30 1986-12-30 Chevron Research Company Resistive hydrocarbon leak detector
US4957012A (en) * 1989-06-16 1990-09-18 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Predictive aging of polymers
US5019760A (en) 1989-12-07 1991-05-28 Electric Power Research Institute Thermal life indicator
EP0442205A3 (en) * 1990-01-25 1992-05-06 Westinghouse Electric Corporation Method for monitoring the effects of thermal and radiation exposure
US5317252A (en) * 1992-09-15 1994-05-31 Kranbuehl David E Dosimeter for monitoring the condition of polymeric materials and chemical fluids
US5432435A (en) * 1992-09-22 1995-07-11 Brigham Young University Detection of cross-linking in pre-cure stage polymeric materials by measuring their impedance
US6037180A (en) * 1996-03-08 2000-03-14 Minnesota Mining And Manufacturing Company Method for measuring the quantity of a polymeric or pre-polymeric composition
JP3625348B2 (en) * 1996-12-10 2005-03-02 Ｔｄｋ株式会社 Moisture sensitive element
US6004817A (en) * 1997-04-04 1999-12-21 3M Innovative Properties Company Method for measuring stress levels in polymeric compositions
US6276214B1 (en) * 1997-12-26 2001-08-21 Toyoaki Kimura Strain sensor functioned with conductive particle-polymer composites
US6495069B1 (en) 1998-01-30 2002-12-17 Peratech Limited Of A Company Of Great Britain And Northern Ireland Polymer composition
JP2003534528A (en) * 1999-11-19 2003-11-18 バッテル・メモリアル・インスティチュート Mechanical fluid analyzer
TW515890B (en) * 2000-09-25 2003-01-01 Jsr Corp Anisotropically conductive sheet, production process thereof and applied product thereof
US6802446B2 (en) * 2002-02-01 2004-10-12 Delphi Technologies, Inc. Conductive adhesive material with metallurgically-bonded conductive particles
US6819120B2 (en) * 2002-11-13 2004-11-16 Northrop Grumman Corporation Non-contact surface conductivity measurement probe
US7921727B2 (en) * 2004-06-25 2011-04-12 University Of Dayton Sensing system for monitoring the structural health of composite structures
US7924031B2 (en) * 2005-02-23 2011-04-12 Watkins Jr Kenneth S Health monitoring method for composite materials
WO2006091631A2 (en) * 2005-02-23 2006-08-31 Watkins Kenneth S Jr Degradation sensor for environmentally sensitive products and method of use

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4520341A (en) * 1981-12-08 1985-05-28 Sharp Kabushiki Kaisha Moisture responsive element with crosslinked organic membrane and protective layering
US4988875A (en) * 1988-12-13 1991-01-29 At&T Bell Laboratories Near infrared polyethylene inspection system and method
US5789665A (en) * 1996-04-25 1998-08-04 Voelker Sensors, Inc. Oil quality sensor for use in a motor

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP1490672A2 *

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2005081930A3 (en) * 2004-02-24 2006-03-09 Polymer Aging Concepts Inc Heath monitoring method and apparatus for composite materials
WO2005081930A2 (en) 2004-02-24 2005-09-09 Polymer Aging Concepts, Inc. Heath monitoring method and apparatus for composite materials
US7924031B2 (en) 2005-02-23 2011-04-12 Watkins Jr Kenneth S Health monitoring method for composite materials
US7382263B2 (en) 2005-05-20 2008-06-03 Dow Global Technologies Inc. Oral drug compliance monitoring using radio frequency identification tags
US7659728B1 (en) 2006-08-23 2010-02-09 Watkins Jr Kenneth S Method and apparatus for measuring degradation of insulation of electrical power system devices
US7990156B1 (en) 2006-08-23 2011-08-02 Watkins Jr Kenneth S Method and apparatus for measuring degradation of insulation of electrical power system devices
US8511174B2 (en) 2007-07-02 2013-08-20 Contitech Ag Strain sensor and corresponding sensor arrangement
WO2009003853A2 (en) 2007-07-02 2009-01-08 Contitech Ag Expansion sensor and corresponding sensor arrangement
US7612325B1 (en) 2007-08-22 2009-11-03 Watkins Jr Kenneth S Electrical sensor for monitoring degradation of products from environmental stressors
WO2012026993A1 (en) * 2010-08-26 2012-03-01 The Boeing Company Automated tire inspections utilizing conductive filaments
US8706446B2 (en) 2010-08-26 2014-04-22 The Boeing Company Automated tire inspections utilizing conductive filaments
US9002661B2 (en) 2010-08-26 2015-04-07 The Boeing Company Automated tire inspections utilizing fluorescing nano-particles
US8812251B2 (en) 2011-04-12 2014-08-19 The Boeing Company System and method for monitoring bonding integrity
US9267906B2 (en) 2011-04-12 2016-02-23 The Boeing Company Bondline embedded current sensor
US9567104B2 (en) 2011-04-12 2017-02-14 The Boeing Company Utilization of aircraft bondline embedded current sensors in the determination of a lightning damage index
PT106994A (en) * 2013-06-09 2014-12-09 Active Space Technologies Actividades Aeroespaciais Lda METHOD AND MONITORING SYSTEM FOR AGING ELECTRIC WIRING
CN104713818A (en) * 2013-12-17 2015-06-17 甘肃金海新材料有限公司 Replacement and maintenance method for sand prevention net and sand prevention net evaluation method
US11865931B2 (en) 2018-10-17 2024-01-09 Robert Bosch Gmbh Line set for a charging station, charging station
RU193046U1 (en) * 2019-07-10 2019-10-11 федеральное государственное автономное образовательное учреждение высшего образования "Санкт-Петербургский политехнический университет Петра Великого" (ФГАОУ ВО "СПбПУ") Coaxial cylindrical electrode system for measuring the frequency dependence of the conductivity of composite materials

Also Published As

Publication number Publication date
US7414416B2 (en) 2008-08-19
AU2003225688A8 (en) 2003-09-22
US7663381B2 (en) 2010-02-16
US20050268734A1 (en) 2005-12-08
EP1490672A4 (en) 2005-09-21
US20080307909A1 (en) 2008-12-18
EP1490672A2 (en) 2004-12-29
ATE538373T1 (en) 2012-01-15
EP1490672B1 (en) 2011-12-21
WO2003076953A3 (en) 2004-05-27
AU2003225688A1 (en) 2003-09-22

Similar Documents

Publication Publication Date Title
US7414416B2 (en) Electrical condition monitoring method for polymers
US7924031B2 (en) Health monitoring method for composite materials
Bowler et al. Aging mechanisms and monitoring of cable polymers
CN108051364A (en) A kind of EPR nuclear energy cable residue lifetime estimation method and prediction EPR nuclear energy cable remaining life methods
WO2005081930A2 (en) Heath monitoring method and apparatus for composite materials
Fantoni Condition monitoring of electrical cables using line resonance analysis (LIRA)
Berger et al. Spread spectrum techniques for measurement of dielectric aging on low voltage cables for nuclear power plants
JPH03179245A (en) Diagnosis of aging of electric wire and cable
Gagliani et al. Capacitance measurements for nondestructive testing of aged nuclear power plant cable
JP7223037B2 (en) Non-Destructive Test Method, Apparatus and Program for Elastomer Cable Insulation Sheath
Glass et al. Dielectric Spectroscopy for Bulk Condition Assessment of Low Voltage Cable--Interim Report
Rouison et al. How Can Material Characterization Support Cable Aging Management?
Tamus Regression analysis to evaluate the reliability of insulation diagnostic methods
Watkins Jr et al. An Electrical Condition Monitoring Approach for Wire and Cable
CA2118197C (en) Measurement of cross-linking by products in crosslinked polyethylene
JP2636448B2 (en) Diagnosis method for wire / cable deterioration
Behera et al. Cable aging phenomena under accelerated aging conditions
Ohki et al. Successful detection of insulation degradation in cables by frequency domain reflectometry
JP2001264376A (en) Cable inspection method
Sun A paper submitted to Materials Evaluation Weixing Sun, Rui Ding, and Nicola Bowler Department of Materials Science and Engineering, Iowa State University, Ames, IA 50011 USA
Lofaro et al. An evaluation of condition monitoring techniques for low-voltage electric cables
JPH08219966A (en) Method for diagnosing deterioration of wire/cable
Afia et al. Investigating the Complex Permittivity of Low Voltage Power Cables Under Different Stresses
JPH04198750A (en) Insulation deterioration diagnostic method for electric wire
Lofaro et al. Aging and condition monitoring of electric cables in nuclear power plants

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A2

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EC EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NO NZ OM PH PL PT RO RU SD SE SG SK SL TJ TM TN TR TT TZ UA UG US UZ VN YU ZA ZM ZW

AL Designated countries for regional patents

Kind code of ref document: A2

Designated state(s): GH GM KE LS MW MZ SD SL SZ TZ UG ZM ZW AM AZ BY KG KZ MD RU TJ TM AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LU MC NL PT RO SE SI SK TR BF BJ CF CG CI CM GA GN GQ GW ML MR NE SN TD TG

121 Ep: the epo has been informed by wipo that ep was designated in this application
WWE Wipo information: entry into national phase

Ref document number: 2003744208

Country of ref document: EP

WWP Wipo information: published in national office

Ref document number: 2003744208

Country of ref document: EP

WWE Wipo information: entry into national phase

Ref document number: 10506518

Country of ref document: US

NENP Non-entry into the national phase

Ref country code: JP

WWW Wipo information: withdrawn in national office

Country of ref document: JP