NL1031878C2 - Non-destructive testing. - Google Patents

Non-destructive testing. Download PDF

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Publication number
NL1031878C2
NL1031878C2 NL1031878A NL1031878A NL1031878C2 NL 1031878 C2 NL1031878 C2 NL 1031878C2 NL 1031878 A NL1031878 A NL 1031878A NL 1031878 A NL1031878 A NL 1031878A NL 1031878 C2 NL1031878 C2 NL 1031878C2
Authority
NL
Netherlands
Prior art keywords
fiber
method
pipeline
material
reinforced
Prior art date
Application number
NL1031878A
Other languages
Dutch (nl)
Inventor
Harald Erik Niklaus Bersee
Tahira Jabeen Ahmed
Giovanni Francisco Nino
Original Assignee
Netherlands Inst For Metals Re
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 Netherlands Inst For Metals Re filed Critical Netherlands Inst For Metals Re
Priority to NL1031878A priority Critical patent/NL1031878C2/en
Priority to NL1031878 priority
Application granted granted Critical
Publication of NL1031878C2 publication Critical patent/NL1031878C2/en

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Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N25/00Investigating or analyzing materials by the use of thermal means
    • G01N25/72Investigating presence of flaws
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/44Resins; rubber; leather
    • G01N33/442Resins, plastics

Description

Non-destructive testing

The present invention relates to a method for the non-destructive testing of fiber-reinforced polymer material, comprising external infrared inspection for an infrared detector and evaluating the results.

Two methods are generally known in the art for the non-destructive testing of fiber-reinforced polymer material. The first and most accurate is ultrasonic scanning. However, this method has the disadvantage of requiring considerable labor and costs. Inspection must be achieved on a point-to-point basis.

An alternative that allows inspection of larger surfaces is based on infrared thermography. According to a first aspect, the object to be examined has a temperature deviation from the temperature of the room in which it is introduced and an investigation is carried out by an infrared sensor such as an infrared camera.

According to a second approach, the object in question is heated externally during observation by the infrared camera.

Although thermal image processing techniques are simpler than the ultrasonic scanning technique, it is much more difficult to distinguish such errors.

It is the object of the present invention to provide a method which allows investigation by area and not from point to point but on the other hand gives a clear indication if errors are present in the fiber-reinforced polymer material.

According to the present invention, this is achieved by heating that fiber-reinforced polymer material internally before or during that infrared examination.

According to the invention, internal heating is used. This is in contrast to the prior art, in which external heating was used. Through the use of internal heating, the depth over which investigation can be realized is much greater, resulting in better images, which makes it easier to detect errors.

According to a preferred embodiment, internal heating is achieved electrically. To that end, resistance wires extend in the fiber-reinforced polymer material and are connected to a voltage source. Different heating wires can be connected in parallel and voltage can be put on common bus bars.

In case an error exists in the fiber-reinforced polymer material, this will have an effect on the heat conduction of the electric heating elements to the exterior of the object in question. This difference in heat conduction with respect to the environment or where such an error does not exist can be clearly distinguished in an image produced by an infrared camera.

If the article comprises a fiber-reinforced polymer that will be useful in high strength applications, the electrical wiring is preferably included in the fiber gain. However, it is also possible to include such a wiring as a separate part. In all cases, the material of the electrical wiring is selected such that the required heat generation is generated. Depending on the requirements, the material for resistance wires can be chosen. If a regular check is necessary and the article is in a corrosive environment, it may be preferable to use a stainless wiring. The diameter of the individual wires can be selected as desired, such as between 50 and 250 μιη and as an example a value of about 100 μιη diameter for the wiring is mentioned.

The wiring can be in any position in the thickness of the fiber-reinforced polymer material. However, this is preferably arranged near the side which is away from the infrared sensor such as an infrared camera. In this way there will be no disturbance of the electrical resistance wire on the image and an optimum image over the thickness of the material is obtained by the infrared sensor.

The sensitivity can be improved by using lock-in techniques to increase sensitivity and filter out irrelevant noise.

The resistive wires can comprise both metallic and organic conductive material.

There are many areas where the invention can be used. The study of aerodynamic profiles such as aviation structures is mentioned as a non-limiting example. Heavy-duty components can be examined on a regular basis with relatively simple means with the simple use of a voltage source and an infrared camera. The wiring in question can be permanently connected to a voltage source so that investigation can be carried out by simply switching and placing the camera. An example is the front edge of a wing.

Another area concerns pipelines. More in particular where high-pressure pipelines are made from fiber-reinforced material, regular testing may be necessary. Another application is the manufacture of such a pipeline on the construction site. For some applications, it is advantageous to manufacture pipelines on site to keep transport costs as low as possible and to achieve large lengths. However, if pipes or other fiber-reinforced polymer articles are produced on site, a thorough investigation is necessary. The method as described above can easily be used for this purpose. For example, a length of 1-5 m can be examined in a single step after it is provided, the resistance wiring during its production for internal heating of the manufactured pipeline.

It has been found that the power requirement is relatively low, so that there is no risk of damaging the fiber-reinforced polymer material in question during heating.

The invention will be further elucidated with reference to the drawings, in which: 1a, b schematically show the method according to the invention;

FIG. 2 schematically shows an electrical series according to the invention;

FIG. 3 schematically shows a pipeline made with faults;

FIG. 4 shows various positions on the electrical wiring;

FIG. 5 shows a photograph of the different layers shown in FIG. 4; FIG. 6 shows the position of various errors in a flat panel; and

FIG. 7 shows the results of the examination of the panel according to FIG.

In Fig. 1, a fiber-reinforced polymer article to be examined is indicated in its entirety by 1. An error has reference numeral 2, while this fiber-reinforced polymer article is provided with a heat-emitting layer 3. In Figure 1, the effect of the expansion of the heat shown with arrows 4 and 5. It is clear that at the location of the defect 2 heat will not be conducted so easily to adjacent parts of object 1. In Fig. 1b an infra-red camera 6 is shown which image of the object in question. It will be appreciated that at the surface of the object observed by the camera near the location of the error, the rise in temperature over time will be less than at other locations, which gives a clear indication in the resulting image that a error is present.

FIG. 2 shows an example for a heat-emitting layer 3. Two current collectors 7 and 8 are present between which electrically conductive wires extend. These can have a diameter of less than 100 μπι and can, for example, comprise stainless steel. Voltage is applied via a voltage source 10. Electrically conductive wires can be included in reinforcement fibers such as glass fibers.

FIG. 3 schematically shows a pipeline 12 comprising three fiber layers 13-15 reinforcing material. Layers A-C are present in layers 13, 14 and 15.

FIG. 4 shows the recording of a series of electrically conductive resistance wires 31, as shown in FIG. 1 in the embodiment according to FIG. 3. The position of the errors A-C is also shown. FIG. 5 shows the images obtained with camera 6 facing the outside of the pipeline 12 of FIGS. 3 and 4.

FIG. 5A shows defect A, while figures 5B and 5C show defect B and C, respectively.

FIG. 6 shows a laminate comprising three layers A, B and C as well as a series of electrical resistance wires in the bottom of the laminate.

FIG. 7 shows the corresponding images obtained from the layers A-C.

It will be understood that other objects can be examined with the method according to the invention.

Example

Referring to FIGS. 3-5, an inner layer of 95 mm diameter with filament is wound over a steel doom. Fiberglass mat was used with an epoxy matrix to produce a pipeline with a wall thickness of 8.25 mm. A series of Teflon inserts (0.5 mm thick) with dimensions ranging between 20 x 20 mm and 5 x 5 30 mm was placed at different depths of the part during the winding process to simulate errors.

The method according to the invention with internal heating and more particularly internal pulse heating was used for detecting the relevant defects. This was achieved with an E020-3 Delta Elektronika power supply with a range of 0-3A and 0-30V. The electrical resistance wiring included a stainless steel metallic wires. Voltage and current were adjusted for appropriate heating of the samples. A single heating pulse is sufficient for proper error detection using the infrared camera. Modulated thermography was used to improve the sensitivity of the camera and to more easily detect errors. An error correction analysis is performed with either a sub-phase or harmonic approximation method to generate the images. All phase images were prepared from the transient heating image sequences. The result obtained corresponds to what is shown in FIG.

Although the invention relates to preferred embodiments described above, it will be immediately apparent to those skilled in the art that the invention has many other applications where non-destructive testing is essential. These are within the scope of the appended claims.

t031878

Claims (13)

  1. Method for the non-destructive examination of fiber-reinforced polymer material, comprising external infrared examination with an infrared detector and evaluation of the results thereof, characterized in that before or during that infrared examination that fiber-reinforced polymer material is internally heated by a heat-emitting layer .
  2. Method according to claim 1, wherein said internal heating is electric.
  3. 3. Method as claimed in claim 2, wherein said internal heating with resistance wires is realized.
  4. Method according to any of the preceding claims, wherein said fiber-reinforced polymer material is heated with a series-like heating element.
  5. 5. Method as claimed in any of the foregoing claims, wherein said internal heating is realized at the side of the fiber-reinforced material away from the infrared detector.
  6. The method of any one of the preceding claims, wherein said fiber-reinforced polymer material is fiber-reinforced. 25
  7. Method according to claims 3 and 5, wherein the resistance wires extend in the same direction as that fiber.
  8. 8. Method as claimed in any of the foregoing claims, in combination with claim 6, wherein said fiber comprises a non-conductive material.
  9. A method according to any one of the preceding claims, wherein said material contains an aerodynamic profile. 1031878
  10. The method of any one of the preceding claims, wherein said material comprises a pipeline.
  11. 11. A method for manufacturing a fiber-reinforced pipeline, comprising manufacturing a pipeline at the site of use, wherein the production of the pipeline comprises incorporating heatable array of electrical resistance wires present near the inside of the pipeline in that material formed by electrically heating said wires and externally examining said pipeline with an infrared camera with the method according to claim 1. 10
  12. The method of claim 11, wherein the examination comprises scanning a length of the pipeline with said infrared camera.
  13. 13. Method as claimed in any of the foregoing claims, wherein said internal heating is used for removing ice / preventing ice formation. 1031878
NL1031878A 2006-05-24 2006-05-24 Non-destructive testing. NL1031878C2 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
NL1031878A NL1031878C2 (en) 2006-05-24 2006-05-24 Non-destructive testing.
NL1031878 2006-05-24

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NL1031878A NL1031878C2 (en) 2006-05-24 2006-05-24 Non-destructive testing.
PCT/NL2007/050234 WO2007136264A1 (en) 2006-05-24 2007-05-21 Non-destructive testing of composite structures

Publications (1)

Publication Number Publication Date
NL1031878C2 true NL1031878C2 (en) 2007-11-27

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Family Applications (1)

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NL1031878A NL1031878C2 (en) 2006-05-24 2006-05-24 Non-destructive testing.

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NL (1) NL1031878C2 (en)
WO (1) WO2007136264A1 (en)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009141472A1 (en) * 2008-05-20 2009-11-26 Antonio Miravete De Marco System and method for monitoring damage to structures
US9091657B2 (en) 2010-01-26 2015-07-28 Metis Design Corporation Multifunctional CNT-engineered structures
EP2769597B1 (en) 2011-08-30 2019-05-01 Watlow Electric Manufacturing Company High definition heater and method of operation
US9518946B2 (en) 2013-12-04 2016-12-13 Watlow Electric Manufacturing Company Thermographic inspection system
RU2571453C1 (en) * 2014-10-27 2015-12-20 Открытое акционерное общество "Центральный научно-исследовательский институт специального машиностроения" Method for control of electroconductive polymer composite materials
CZ2014742A3 (en) 2014-11-03 2016-04-20 Vysoké Učení Technické V Brně Method of evaluating degradation, density and orientation of ferromagnetic electrically conducting fibers within composite material and detection device for making the same
RU2690033C1 (en) * 2018-09-14 2019-05-30 Акционерное общество "Центральный научно-исследовательский институт специального машиностроения" (АО "ЦНИИСМ") Method of electric power thermography of spatial objects and device for its implementation

Citations (2)

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WO2001029545A1 (en) * 1999-10-16 2001-04-26 Airbus Uk Limited Material analysis
WO2003069324A1 (en) * 2002-02-15 2003-08-21 Lm Glasfiber A/S A method and an apparatus for the detection of the presence of polymer in a wind turbine blade

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US20040120383A1 (en) * 2002-12-19 2004-06-24 The Boeing Company Non-destructive testing system and method using current flow thermography

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001029545A1 (en) * 1999-10-16 2001-04-26 Airbus Uk Limited Material analysis
WO2003069324A1 (en) * 2002-02-15 2003-08-21 Lm Glasfiber A/S A method and an apparatus for the detection of the presence of polymer in a wind turbine blade

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
STEINBERGER ET AL: "Infrared thermographic techniques for non-destructive damage characterization of carbon fibre reinforced polymers during tensile fatigue testing" INTERNATIONAL JOURNAL OF FATIGUE, BUTTERWORTH SCIENTIFIC LTD, GUILDFORD, GB, [Online] deel 28, nr. 10, 18 april 2006 (2006-04-18), bladzijden 1340-1347, XP005558985 ISSN: 0142-1123 Gevonden op het Internet: URL:http://www.sciencedirect.com> [gevonden op 2006-01-23] *

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Effective date: 20080818

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Effective date: 20091201