WO1998040732A1 - Magnetometer detection of fatigue damage in aircraft - Google Patents
Magnetometer detection of fatigue damage in aircraft Download PDFInfo
- Publication number
- WO1998040732A1 WO1998040732A1 PCT/US1998/005027 US9805027W WO9840732A1 WO 1998040732 A1 WO1998040732 A1 WO 1998040732A1 US 9805027 W US9805027 W US 9805027W WO 9840732 A1 WO9840732 A1 WO 9840732A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- fatigue
- conductivity
- mwm
- aircraft
- sensor
- Prior art date
Links
Classifications
-
- 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
- G01N27/72—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables
- G01N27/82—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables for investigating the presence of flaws
- G01N27/90—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables for investigating the presence of flaws using eddy currents
- G01N27/9046—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables for investigating the presence of flaws using eddy currents by analysing electrical signals
Definitions
- Aircraft as with most structural elements, deteriorate with age.
- the deterioration can be from various influences such as corrosion from weather or fatigue.
- Fatigue is generally defined as the gradual deterioration of a material which is subjected to repeated loads.
- the loading can occur from various factors created by the pressurization of the fuselage, turbulence, air lifting the plane, the landing loads and the addition and removal of weight such as fuel, passengers and freight.
- the structures that are of concern can include frames 36, bulkheads 38, ribs 40, spars 42, mounting pylons 44, and skins panels 46.
- a previous technique of non-destructive testing for detecting the condition of the aircraft was liquid penetrant or conventional eddy current sensing.
- FIG. 5A shows a MWM sensor 54 inspecting a landbased turbine blade.
- This MWM probe is capable of inspecting flat, convex, concave and tapered surfaces, without requiring recalibration for new curvatures.
- An improved version is shown in Figure 5B.
- Calibration and absolute property measurement using air calibration are discussed in U.S. Patent Application No. 08/702,276 titled “Meandering Winding Test Circuit (Amended)" which was filed on August 23, 1996, and U.S. Patent Application No. 60/063,534 titled “Absolute Property Measurement with Air Calibration" which was filed on October 29, 1997, the entire contents of which are incorporated herein by reference. While the probe shown is approximately the size of a human fist, smaller probe holders, such as 56 shown in Figure 5B, can also be used with the half inch by half inch footprint MWM shown. A quarter inch by quarter inch MWM uses an even smaller probe.
- Figure 6B illustrates measurement grids 64 for ferrous steel. Note that the lift-off lines for aluminum from Figure 6A are practically perpendicular to those of ferrous steel.
- the MWM continuum models then solve a one dimensional magnetic diffusion equation along the y axis in the winding plane to compute the magnetic vector potential and surface current density distributions as a function of y (see Figure 2 for axis orientation) .
- a subdomain method of weighted residuals is used for this purpose. This process accounts for the winding geometry.
- the relevant two port admittances (Y12, Yll, and Y22) are computed and the MWM response is determined, in terms of the magnitude and phase of the transfer inductance.
- diagnosis of aging aircraft problems such as WFD will require identification of specific "markers" that must be present for a widespread fatigue problem to exist.
- assembly of the floorboard on certain aircraft results in plastic deformation of an area on the outer skin near the floor board fastener row. In prior methods this could be confused for WFD.
- This damage is not, however, concentrated near the surface, as is characteristic of fatigue damage, but rather occurs throughout the skin. Thus, knowledge of the damage depth profile is used to distinguish this area of plastic deformation from fatigue damage.
Abstract
Description
Claims
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE69814601T DE69814601T2 (en) | 1997-03-13 | 1998-03-13 | MAGNETOMETRIC DETECTION OF FATIGUE DAMAGE IN AIRCRAFT |
EP98912933A EP0966676B1 (en) | 1997-03-13 | 1998-03-13 | Magnetometer detection of fatigue damage in aircraft |
AU67608/98A AU6760898A (en) | 1997-03-13 | 1998-03-13 | Magnetometer detection of fatigue damage in aircraft |
CA002282650A CA2282650A1 (en) | 1997-03-13 | 1998-03-13 | Magnetometer detection of fatigue damage in aircraft |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US3962297P | 1997-03-13 | 1997-03-13 | |
US60/039,622 | 1997-03-13 | ||
US4195897P | 1997-04-03 | 1997-04-03 | |
US60/041,958 | 1997-04-03 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1998040732A1 true WO1998040732A1 (en) | 1998-09-17 |
Family
ID=26716308
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1998/005027 WO1998040732A1 (en) | 1997-03-13 | 1998-03-13 | Magnetometer detection of fatigue damage in aircraft |
Country Status (6)
Country | Link |
---|---|
US (1) | US6420867B1 (en) |
EP (1) | EP0966676B1 (en) |
AU (1) | AU6760898A (en) |
CA (1) | CA2282650A1 (en) |
DE (1) | DE69814601T2 (en) |
WO (1) | WO1998040732A1 (en) |
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US6545469B1 (en) | 2001-10-31 | 2003-04-08 | General Electric Company | Embedded eddy current inspection apparatus, system, and method |
US6657429B1 (en) | 1995-08-25 | 2003-12-02 | Jentek Sensors, Inc. | Material condition assessment with spatially periodic field sensors |
GB2396427A (en) * | 1999-09-20 | 2004-06-23 | Jentek Sensors Inc | Eddy-current sensor arrays |
GB2400445A (en) * | 1999-09-20 | 2004-10-13 | Jentek Sensors Inc | Eddy current test circuit |
FR2885697A1 (en) * | 2005-05-13 | 2006-11-17 | Electricite De France | Metal component inspection, e.g. piping, for e.g. pressurized water reactor, involves determining characterization of open defects of component from conductivity variations evaluated from measurements of eddy currents of component |
US7161350B2 (en) | 1999-09-07 | 2007-01-09 | Jentek Sensors, Inc. | Method for material property monitoring with perforated, surface mounted sensors |
US7994781B2 (en) | 1999-09-20 | 2011-08-09 | Jentek Sensors, Inc. | Eddy current sensor with concentric segments |
US9260200B1 (en) | 2014-11-07 | 2016-02-16 | International Business Machines Corporation | Metal fatigue analytics and alert systems |
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US7518359B2 (en) * | 2005-03-09 | 2009-04-14 | General Electric Company | Inspection of non-planar parts using multifrequency eddy current with phase analysis |
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- 1998-03-13 DE DE69814601T patent/DE69814601T2/en not_active Expired - Lifetime
- 1998-03-13 AU AU67608/98A patent/AU6760898A/en not_active Abandoned
- 1998-03-13 CA CA002282650A patent/CA2282650A1/en not_active Abandoned
- 1998-03-13 EP EP98912933A patent/EP0966676B1/en not_active Expired - Lifetime
- 1998-03-13 US US09/039,190 patent/US6420867B1/en not_active Expired - Lifetime
- 1998-03-13 WO PCT/US1998/005027 patent/WO1998040732A1/en active IP Right Grant
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Cited By (19)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6657429B1 (en) | 1995-08-25 | 2003-12-02 | Jentek Sensors, Inc. | Material condition assessment with spatially periodic field sensors |
US6380747B1 (en) | 1998-05-12 | 2002-04-30 | Jentek Sensors, Inc. | Methods for processing, optimization, calibration and display of measured dielectrometry signals using property estimation grids |
US7161350B2 (en) | 1999-09-07 | 2007-01-09 | Jentek Sensors, Inc. | Method for material property monitoring with perforated, surface mounted sensors |
US7348771B2 (en) | 1999-09-07 | 2008-03-25 | Jentek Sensors, Inc. | Method for verifying sensor condition |
US7589526B2 (en) | 1999-09-20 | 2009-09-15 | Jentek Sensors, Inc. | Surface mounted sensor arrays having segmented primary windings |
WO2001022076A1 (en) * | 1999-09-20 | 2001-03-29 | Jentek Sensors, Inc. | Eddy-current sensor arrays |
GB2377028B (en) * | 1999-09-20 | 2004-07-28 | Jentek Sensors Inc | Eddy-current sensor arrays |
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GB2396427B (en) * | 1999-09-20 | 2004-10-13 | Jentek Sensors Inc | Method of monitoring damage at a fastener using an eddy-current sensor |
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US7994781B2 (en) | 1999-09-20 | 2011-08-09 | Jentek Sensors, Inc. | Eddy current sensor with concentric segments |
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US9260200B1 (en) | 2014-11-07 | 2016-02-16 | International Business Machines Corporation | Metal fatigue analytics and alert systems |
US9430540B2 (en) | 2014-11-07 | 2016-08-30 | International Business Machines Corporation | Metal fatigue analytics and alert systems |
Also Published As
Publication number | Publication date |
---|---|
US6420867B1 (en) | 2002-07-16 |
DE69814601D1 (en) | 2003-06-18 |
EP0966676B1 (en) | 2003-05-14 |
AU6760898A (en) | 1998-09-29 |
DE69814601T2 (en) | 2004-04-01 |
EP0966676A1 (en) | 1999-12-29 |
CA2282650A1 (en) | 1998-09-17 |
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