Method for real-time ultrasonic testing system

• US 5,777,891 A
• Filed: 08/23/1996
• Issued: 07/07/1998
• Est. Priority Date: 05/07/1991
• Status: Expired due to Term

• Current Assignee: Dap Industries Inc., Harsco Technologies Corporation (Harsco Corporation)
• Original Assignee: Dapco Industries, Inc. (Westinghouse Air Brake Technologies Corporation)
• Inventors: Mackay, Brian, Norris, James, Pagano, Dominick
• Primary Examiner(s): ZANELLI, MICHAEL J
• Application Number:
  US08/703,616
• Time in Patent Office: 683 Days
• Field of Search: 364/552, 364/550, 364/551.01, 364/507, 364/508, 364/217, 73/635, 73/636, 73/639, 73/641, 73/598, 73/602
• US Class Current: 702/39
• CPC Class Codes: G01N 2291/011 Velocity or travel time
• CPC Class Codes: G01N 2291/0421 Longitudinal waves
• CPC Class Codes: G01N 2291/0422 Shear waves, transverse waves, horizontally polarised waves
• CPC Class Codes: G01N 2291/044 Internal reflections (echoes), e.g. on walls or defects
• CPC Class Codes: G01N 2291/056 Angular incidence, angular propagation
• CPC Class Codes: G01N 2291/2623 Rails; Railroads
• CPC Class Codes: G01N 29/0609 Display arrangements, e.g. colour displays indicating or recording in connection with measuring in general G01D
• CPC Class Codes: G01N 29/07 by measuring propagation velocity or propagation time of acoustic waves
• CPC Class Codes: G01N 29/11 by measuring attenuation of acoustic waves
• CPC Class Codes: G01N 29/2487 Directing probes, e.g. angle probes directing arrangements G01N29/221
• CPC Class Codes: G01N 29/2493 Wheel shaped probes
• CPC Class Codes: G01N 29/265 by moving the sensor relative to a stationary material
• CPC Class Codes: G01N 29/30 Arrangements for calibrating or comparing, e.g. with standard objects
• CPC Class Codes: G01N 29/4427 with stored values, e.g. threshold values
• CPC Class Codes: G01N 29/4463 Signal correction, e.g. distance amplitude correction [DAC], distance gain size [DGS], noise filtering

Abstract

An ultrasonic real-time inspection method which is user-friendly in an interactive environment to provide ease of operation, as well as a combination of consistency, thoroughness, and speed of operation in flaw detection not achievable by other methods. The method offers significantly increased pattern recognition capability, which provides greater automation potential and reduced missed detection and false alarm rates.

Claims

1. A method for examining railroad rails for flaws using ultrasonic investigation techniques and for identifying flaws in the rail on a real-time basis, comprising the steps of:

repetitively and regularly injecting pulses of a plurality of ultrasonic beams into the rails from test devices mounted on a vehicle traveling along the rails, and detecting within the test devices acoustic echoes caused at rail discontinuities by the ultrasonic-beams to produce electrical signals representative of the magnitude of the acoustic echoes;

determining travel times of the acoustic echoes to the place of injection into the rails of the beams which caused the acoustic echoes;

while said ultrasonic beams are repetitively and regularly injected into the rails, deriving from said travel times, angles of travel, beam pulse speeds, and beam spreads of the ultrasonic beams inside the rails, spatial signals representative of the locations of the discontinuities along the rails;

combining spatial signals located within slices of the rails to identify and locate flaws in and along the rails while said ultrasonic beams are repetitively and regularly activated including the steps of storing information representative of normal patterns of known rail discontinuities and manufactured contexts, comparing combined spatial signals with said stored information to detect and identify unknown discontinuities and to one of eliminate and reclassify those discontinuities inconsistent with recognized context; and

indicating the locations of said rail discontinuities.

2. The method for examining railroad rails as set forth in claim 1 wherein said combining step further comprises:

determining depth inside the rails of a discontinuity and the ultrasonic beams which caused echoes therefrom;

grouping spatial signals related to said discontinuity; and

deriving from said grouping a basic anomaly recognition of spatially-correlated flaw patterns comprising bolt holes and surface cracks.

3. The method of claim 2, wherein said combining step further comprises the steps of:

storing a plurality of patterns which consist of a grammar requirement defining a sequence of basic anomalies and a position requirement specifying the relative position of each basic anomaly to all others in the pattern;

comparing grouped spatial signals within the context of those stored patterns in rail volumes;

deriving from results of comparison a high level recognition of flaws and the locations of flaws in the rails, whereby flaws inconsistent with recognized context are one of eliminated and reclassified.

4. A method for examining railroad rails for flaws using ultrasonic investigation technique and for identifying flaws in the rail on a real-time basis, comprising the steps of

repetitively and regularly injecting pulses of a plurality of ultrasonic beams into the rails from test wheels mounted to travel along the rails, and detecting within the test wheels acoustic echoes caused at rail discontinuities by the ultrasonic beams to produce electrical signals representative of the acoustic echoes;

determining from electrical signals travel times of the acoustic echoes to the place of injection into the rails of the beams which caused the acoustic echoes;

while said ultrasonic beams are repetitively and regularly injected into the rails, deriving from said travel times, angles of travel, beam pulse speeds, and beam spreads of the ultrasonic beams inside the rails, spatial signals representative of the locations of the discontinuities along the rails;

combining spatial signals located within slices of the rail to derive volume counts and orientations of the number of discontinuities encountered in rail volumes formed by combined slices;

determining a distance along which a said detected rail discontinuity does not occur;

generating said volume count when said distance exceeds a predetermined threshold value;

deriving, from said volume counts and orientations, the locations, size, and type of flaws in the rails;

comparing said types of flaws with expected contexts for said flaws in said elongate material to one of eliminate and reclassify those flaws inconsistent with recognized context; and

indicating the location of said flaws while pulses of ultrasonic beams are repetitively and regularly injected.

5. A method for examining an elongate material for flaws using ultrasonic investigation techniques and for identifying flaws in the material on a real-time basis, comprising the steps of:

repetitively and regularly injecting pulses of a plurality of ultrasonic beams into the elongate material from test devices mounted to travel along the elongate material, and detecting within the test devices acoustic echoes caused at material discontinuities by the ultrasonic beams to produce electrical signals representative of the acoustic echoes;

determining travel times of the acoustic echoes to the place of injection into the elongate material of the ultrasonic beams which caused the acoustic echoes;

while said ultrasonic beams are repetitively and regularly injected into the elongate material, deriving from said travel times, angles of travel, beam pulse speeds, and beam spreads of the ultrasonic beams inside the material, spatial signals representative of the locations of the discontinuities along the elongate material;

combining spatial signals located within slices of the elongate material to identify and locate flaws in and along the elongate material, while said ultrasonic beams are repetitively and regularly activated, including the steps of storing information representative of normal patterns of known material discontinuities and manufactured contexts, comparing combined spatial signals with said stored information to detect and identify unknown discontinuities and one of eliminate and reclassify those discontinuities inconsistent with recognized context; and

indicating the locations of said material discontinuities.

6. The method for examining an elongate material as set forth in claim 5 wherein said combining step further comprises:

determining depths inside the elongate material of a discontinuity and the ultrasonic beams which caused echoes therefrom;

grouping spatial signals related to said discontinuity; and

deriving from said grouping a basic anomaly recognition of spatially-correlated flaw patterns.

7. The method as claimed in claim 6 wherein said combining step still further comprises the steps of:

storing a plurality of patterns which consist of a grammar requirement defining a sequence of basic anomalies and a position requirement specifying the relative position of each basic anomaly to all others in the pattern;

comparing grouped spatial signals with said stored patterns;

deriving from results of comparison a high level recognition of flaws and the locations of flaws in the rails.

8. A method for examining an elongate material for flaws using ultrasonic investigation technique and for identifying flaws in the elongate material on a real-time basis, comprising the steps of:

repetitively and regularly injecting pulses of a plurality of ultrasonic beams into the elongate material from test devices mounted to travel along the elongate material and detecting within the test devices acoustic echoes caused at elongate material discontinuities by the ultrasonic beams to produce electrical signals representative of the acoustic echoes;

determining from electrical signals travel times of the acoustic echoes to the place of injection into the elongate material of the beams which caused the acoustic echoes;

while said ultrasonic beams are repetitively and regularly injected into the elongate material, deriving from said travel times angles of travel, beam pulse speeds, and beam spreads of the ultrasonic beams inside the material, spatial signals representative of the locations of the discontinuities along the elongate material;

combining spatial signals located within slices of the elongate material to derive volume counts and orientations of the number of discontinuities encountered in elongate material volumes formed by combined slices;

determining a distance along which a said detected elongate material discontinuity does not occur;

generating said volume count when said distance exceeds a predetermined threshold value;

deriving, from said volume counts and orientations, the locations, size, and type of flaws in the elongate material;

comparing said types of flaws with expected contexts for said flaws in said elongate material to one of eliminate and reclassify types of flaws inconsistent with recognized context; and

indicating the location of said flaws while pulses of ultrasonic beams are repetitively and regularly injected.