UT METHOD OF IDENTIFYING A STUCK JOINT

• US 20100031750A1
• Filed: 08/05/2008
• Published: 02/11/2010
• Est. Priority Date: 08/05/2008
• Status: Active Grant

• Current Assignee: Edison Welding Institute Incorporated
• Original Assignee: Edison Welding Institute Incorporated
• Inventors: Lozev, Margarit, Spencer, Roger, Huang, Ta-Chieh
• Granted Patent: US 8,215,173 B2
• Time in Patent Office: Days
• US Class Current: 73/620
• CPC Class Codes: G01N 2291/0234 Metals, e.g. steel
• CPC Class Codes: G01N 2291/2672 Spot welding
• CPC Class Codes: G01N 29/069 Defect imaging, localisation and sizing using, e.g. time of flight diffraction [TOFD], synthetic aperture focusing technique [SAFT], Amplituden-Laufzeit-Ortskurven [ALOK] technique
• CPC Class Codes: G01N 29/11 by measuring attenuation of acoustic waves

Abstract

An ultrasonic testing method to identify a stuck joint between two workpieces utilizing an ultrasonic probe to transmit ultrasonic (US) beams into the joint area and capture the associated US reflections. The method transmits two separate US beams fired in very close proximity to one another. The probe then captures a plurality of US reflections. The method looks for subtle variations in a high gain A-scan presentation of a high gain reflected beam, while using a low gain US beam to identify the particular region on the high gain A-scan presentation in which to look for signs of a stuck joint. Subtle variations within a particular region of the high gain A-scan presentation identify stuck joints. The method is applicable to metals and nonmetals and is not limited to fusion welding, but may also be used with solid state welds, brazed and soldered joints, and adhesively joined workpieces.

Claims

1. A UT method of identifying a stuck portion of a joint between a first workpiece (100) and a second workpiece (200), comprising:

transmitting a primary US beam and a secondary US beam from an ultrasonic testing probe (300) into an assembly including the first workpiece (100) and the second workpiece (200);

capturing a plurality of US reflections of the primary US beam and the secondary US beam;

creating a high gain A-scan presentation (805) associated with the primary US beam and creating a low gain A-scan presentation (905) associated with the secondary US beam;

identifying a low gain initial pulse representation (910) on the low gain A-scan presentation (905) and identifying a low gain initial pulse representation peak (912);

allocating an interface detection gate (1000) on the high gain A-scan presentation (805) located a gate offset distance (1050) from the low gain initial pulse representation peak (912) to a gate opening point (1010), wherein the interface detection gate (1000) has a gate period (1030) defined by the gate opening point (1010) and a gate closing point (1020), and wherein the interface detection gate (1000) has a gate amplitude (1040); and

analyzing the high gain A-scan presentation (805) within the interface detection gate (1000) and creating a stuck joint portion alert if a portion of the high gain A-scan presentation (805) exceeds the gate amplitude (1040) within the interface detection gate (1000).

2. The method of claim 1, wherein the gate offset distance (1050) positions the interface detection gate (1000) in the proximity of at least one high gain interface reflection representation.

3. The method of claim 2, wherein the at least one high gain interface reflection representation is a first high gain interface reflection representation (840) between the high gain initial pulse representation (810) and a first high gain full back reflection representation (820).

4. The method of claim 2, wherein the at least one high gain interface reflection representation is a second high gain interface reflection representation (850) between a first high gain full back reflection representation (820) and a second high gain full back reflection representation (830).

5. The method of claim 2, wherein the at least one high gain interface reflection representation is a third high gain interface reflection representation (860) beyond a second high gain full back reflection representation (830).

6. The method of claim 1, wherein the gate period (1030) is less than fifty percent of the gate offset distance (1050).

7. The method of claim 1, wherein the gate period (1030) is less than thirty-five percent of the gate offset distance (1050).

8. The method of claim 1, wherein the high gain A-scan presentation (805) includes a high gain initial pulse representation (810) that has a high gain initial pulse representation peak (812) and a high gain initial pulse representation amplitude (814), wherein the gate amplitude (1040) is greater than 15 percent of the high gain initial pulse representation amplitude (814) and less than 40 percent of the high gain initial pulse representation amplitude (814).

9. The method of claim 1, wherein the high gain A-scan presentation (805) includes a high gain initial pulse representation (810) that has a high gain initial pulse representation peak (812) and a high gain initial pulse representation amplitude (814), wherein the gate amplitude (1040) is greater than 20 percent of the high gain initial pulse representation amplitude (814) and less than 30 percent of the high gain initial pulse representation amplitude (814).

10. The method of claim 1, wherein the ultrasonic testing probe (300) is a high-frequency two-dimensional matrix phased-array probe.

11. The method of claim 10, wherein the high-frequency two-dimensional matrix phased-array probe includes at least 100 piezocomposite elements.

12. The method of claim 11, wherein at least 9 piezocomposite elements of the at least 100 piezocomposite elements are electronically grouped together to create an aperture to electronically focus and steer the primary US beam and the secondary US beam.

13. The method of claim 11, wherein at least 16 piezocomposite elements of the at least 100 piezocomposite elements are electronically grouped together to create an aperture to electronically focus and steer the primary US beam and the secondary US beam.

14. The method of claim 1, wherein the joint between the first workpiece (100) and the second workpiece (200) is divided into at least 81 joint portions that are individually analyzed and each joint portion may create a distinct stuck joint portion alert.

15. The method of claim 14, wherein a stuck joint alert is created if the number of distinct stuck joint portion alerts exceeds 10 percent of the number of joint portions.

16. A UT method of identifying a stuck portion of a joint between a first workpiece (100) and a second workpiece (200), comprising:

transmitting a primary US beam and a secondary US beam from an ultrasonic testing probe (300) into an assembly including the first workpiece (100) and the second workpiece (200), wherein the ultrasonic testing probe (300) is a high-frequency two-dimensional matrix phased-array probe;

capturing a plurality of US reflections of the primary US beam and the secondary US beam;

creating a high gain A-scan presentation (805) associated with the primary US beam and creating a low gain A-scan presentation (905) associated with the secondary US beam, wherein the high gain A-scan presentation (805) includes a high gain initial pulse representation (810) that has a high gain initial pulse representation peak (812) and a high gain initial pulse representation amplitude (814);

identifying a low gain initial pulse representation (910) on the low gain A-scan presentation (905) and identifying a low gain initial pulse representation peak (912);

allocating an interface detection gate (1000) on the high gain A-scan presentation (805) located a gate offset distance (1050) from the low gain initial pulse representation peak (912) to a gate opening point (1010), wherein the interface detection gate (1000) has a gate period (1030) defined by the gate opening point (1010) and a gate closing point (1020), and wherein the interface detection gate (1000) has a gate amplitude (1040) that is greater than 15 percent of the high gain initial pulse representation amplitude (814) and less than 40 percent of the high gain initial pulse representation amplitude (814), and wherein the gate offset distance (1050) positions the interface detection gate (1000) in the proximity of at least one high gain interface reflection representation, and wherein the gate period (1030) is less than fifty percent of the gate offset distance (1050); and

analyzing the high gain A-scan presentation (805) within the interface detection gate (1000) and creating a stuck joint portion alert if a portion of the high gain A-scan presentation (805) exceeds the gate amplitude (1040) within the interface detection gate (1000).

17. The method of claim 16, wherein the at least one high gain interface reflection 20 representation is a first high gain interface reflection representation (840) between the high gain initial pulse representation (810) and a first high gain full back reflection representation (820).

18. The method of claim 16, wherein the high-frequency two-dimensional matrix phased-array probe includes at least 100 piezocomposite elements.

19. The method of claim 18, wherein at least 9 piezocomposite elements of the at least 100 piezocomposite elements are electronically grouped together to create an aperture to electronically focus and steer the primary US beam and the secondary US beam.

20. A UT method of identifying a stuck portion of a joint between a first workpiece (100) and a second workpiece (200), comprising:

transmitting a primary US beam and a secondary US beam from an ultrasonic testing probe (300) into an assembly including the first workpiece (100) and the second workpiece (200), wherein the ultrasonic testing probe (300) is a high-frequency two-dimensional matrix phased-array probe including at least 100 piezocomposite elements and at least 9 piezocomposite elements of the at least 100 piezocomposite elements are electronically grouped together to create an aperture to electronically focus and steer the primary US beam and the secondary US beam, and wherein the joint between the first workpiece (100) and the second workpiece (200) is divided into at least 81 joint portions;

capturing a plurality of US reflections of the primary US beam and the secondary US beam for each joint portion;

creating a high gain A-scan presentation (805) associated with the primary US beam and creating a low gain A-scan presentation (905) associated with the secondary US beam for each joint portion, wherein the high gain A-scan presentation (805) includes a high gain initial pulse representation (810) that has a high gain initial pulse representation peak (812) and a high gain initial pulse representation amplitude (814);

identifying a low gain initial pulse representation (910) on the low gain A-scan presentation (905) and identifying a low gain initial pulse representation peak (912) for each joint portion;

allocating an interface detection gate (1000) on the high gain A-scan presentation (805) of each joint portion located a gate offset distance (1050) from the low gain initial pulse representation peak (912) to a gate opening point (1010), wherein each interface detection gate (1000) has a gate period (1030) defined by the gate opening point (1010) and a gate closing point (1020), and wherein each interface detection gate (1000) has a gate amplitude (1040) that is greater than 15 percent of the high gain initial pulse representation amplitude (814) and less than 40 percent of the high gain initial pulse representation amplitude (814), and wherein each gate offset distance (1050) positions each interface detection gate (1000) in the proximity of at least one high gain interface reflection representation, and wherein each gate period (1030) is less than fifty percent of each gate offset distance (1050); and

analyzing each high gain A-scan presentation (805) within the associated interface detection gate (1000) and creating a stuck joint portion alert if a portion of the high gain A-scan presentation (805) exceeds the gate amplitude (1040) within the interface detection gate (1000), and creating a stuck joint alert if the number of distinct stuck joint portion alerts exceeds 10 percent of the number of joint portions.