Hegeon M Kwun

US Patent:

6373245, Apr 16, 2002

Filed:

Sep 21, 2000

Appl. No.:

09/666752

Inventors:

Hegeon Kwun - San Antonio TX
Sang Young Kim - San Antonio TX

Assignee:

Southwest Research Institute - San Antonio TX

International Classification:

G01N 2782

US Classification:

324240, 73643

Abstract:

A method and apparatus is shown for implementing magnetostrictive sensor techniques for the nondestructive evaluation of plate type structures such as walls, vessels, enclosures, and the like. The system includes magnetostrictive sensors specifically designed for application in conjunction with plate type structures or pipes that generate guided waves in the plates or pipes which travel therethrough in a direction parallel to the surface of the plate or pipe. Similarly structured sensors are positioned to detect the guided waves (both incident and reflected) and generate signals representative of the characteristics of the guided waves detected that are reflected from anomalies in the structure such as corrosion pits and cracks. The sensor structure is longitudinal in nature and generates a guided wave having a wavefront parallel to the longitudinal axis of the sensor, and which propagates in a direction perpendicular to the longitudinal axis of the sensor. The generated guided waves propagate in the plate within the path of the propagating wave.

US Patent:

6396262, May 28, 2002

Filed:

May 15, 2001

Appl. No.:

09/855460

Inventors:

Glenn M. Light - San Antonio TX
Hegeon Kwun - San Antonio TX
Sang-Young Kim - San Antonio TX

Assignee:

Southwest Research Institute - San Antonio TX

International Classification:

G01N 2782

US Classification:

324240, 324220, 73643

Abstract:

A method and apparatus is shown for implementing magnetostrictive sensor techniques for the nondestructive short term inspection or long term monitoring of a structure. A plurality of magnetostrictive sensors are arranged in parallel on the structure and includes (a) a thin ferromagnetic strip that has residual magnetization, (b) that is coupled to the structure with a couplant, and (c) a coil located adjacent the thin ferromagnetic strip. By a transmitting coil, guided waves are generated in a transmitting strip and coupled to the structure and propagate along the length of the structure. For detection, the reflected guided waves in the structure are coupled to a receiving strip and are detected by a receiving magnetostrictive coil. Reflected guided waves may represent defects in the structure.

US Patent:

6404189, Jun 11, 2002

Filed:

Dec 18, 2000

Appl. No.:

09/738062

Inventors:

Hegeon Kwun - San Antonio TX
Sang Young Kim - San Antonio TX

Assignee:

Southeast Research Institute - San Antonio TX

International Classification:

G01N 2782

US Classification:

324220, 324240, 73623, 73643

Abstract:

A method and system for implementing magnetostrictive sensor techniques for the nondestructive evaluation of pipeline structures. The system consists of a magnetostrictive sensor instrument unit, a data storage unit, and a plurality of magnetostrictive sensor probes are positioned on an in-line inspection vehicle. The instrumentation unit includes electronics for transmitting excitation pulses to a transmitting magnetostrictive sensor probe as well as electronics for amplifying and conditioning the signals detected by a receiving magnetostrictive sensor probe. The magnetostrictive sensor probes include both plate magnetostrictive sensors and permanent magnets which provide a DC bias magnetic field necessary for magnetostrictive sensor operation. The transmitting and receiving probes are attached to the in-line inspection vehicle by way of mechanical arms on opposing sides of the vehicle. The mechanical arms are spring loaded and are equipped with rollers which maintain the probes at approximately constant distances from the inside diameter of the pipe wall.

US Patent:

6424150, Jul 23, 2002

Filed:

Dec 12, 2000

Appl. No.:

09/734054

Inventors:

Hegeon Kwun - San Antonio TX
Glenn M. Light - San Antonio TX

Assignee:

Southwest Research Institute - San Antonio TX

International Classification:

G01N 2912

US Classification:

324216, 324240, 73636

Abstract:

A method and apparatus is shown for implementing magnetostrictive sensor techniques for the nondestructive evaluation of railroad rails. The system includes magnetostrictive sensors specifically designed for application in conjunction with railroad rails and trains that generate guided waves in the railroad rails which travel therethrough in a direction parallel to the surface of the railroad rail. Similarly structured sensors are positioned to detect the guided waves (both incident and reflected) and generate signals representative of the characteristics of the guided waves detected that are reflected from anomalies in the structure such as transverse defects. The sensor structure is longitudinal in nature and generates a guided wave having a wavefront parallel to the longitudinal axis of the sensor, and which propagates in a direction perpendicular to the longitudinal axis of the sensor. The generated guided waves propagate in the rail within the path of the propagating wave. The reflected waves from these abnormalities are detected using a magnetostrictive sensor.

US Patent:

6429650, Aug 6, 2002

Filed:

Mar 22, 2001

Appl. No.:

09/815219

Inventors:

Hegeon Kwun - San Antonio TX
Sang-Young Kim - San Antonio TX
James F. Crane - San Antonio TX

Assignee:

Southwest Research Institute - San Antonio TX

International Classification:

G01N 2782

US Classification:

324240, 324220, 73643

Abstract:

A method and apparatus is shown for implementing magnetostrictive sensor techniques for the nondestructive evaluation of pipes or tubes. A magnetostrictive sensor generates guided waves in a pipe or tube, which waves travel therethrough in a direction parallel to the longitudinal axis of the pipe or tube. This is achieved by using a magnetized ferromagnetic strip being pressed circumferentially against the pipe or tube. The guided waves are generated in the strip and coupled to the pipe or tube and propagate along the length of said pipe or tube. For detection, the guided waves in said pipe or tube are coupled to the thin ferromagnetic strip and are detected by receiving MsS coils. Reflected guided waves may represent defects in the pipe or tube.

US Patent:

6624628, Sep 23, 2003

Filed:

Jul 17, 2001

Appl. No.:

09/815017

Inventors:

Hegeon Kwun - San Antonio TX
Sang-Young Kim - San Antonio TX
Alfred E. Crouch - San Antonio TX

Assignee:

Southwest Research Institute - San Antonio TX

International Classification:

G01N 2782

US Classification:

324240, 73643

Abstract:

A method and apparatus is shown for implementing magnetostrictive sensor techniques for the nondestructive evaluation of ferromagnetic pipes or tubes. A magnetostrictive sensor generates shear waves and/or torsional waves in ferromagnetic pipes or tubes, which waves travel therethrough in a direction parallel to the longitudinal axis of the pipe. A circumferential magnetization is generated in the ferromagnetic pipe or tube by a DC or low frequency voltage establishing a current along the longitudinal axis and past the magnetostrictive sensor. Reflected shear or torsional waves may represent defects in the pipe or tube.

US Patent:

6779409, Aug 24, 2004

Filed:

Jul 27, 1999

Appl. No.:

09/355177

Inventors:

Hegeon Kwun - San Antonio TX
Gary L. Burkhardt - Adkins TX
Cecil M. Teller - Austin TX

Assignee:

Southwest Research Institute - San Antonio TX

International Classification:

G01L 302

US Classification:

73862333

Abstract:

A device and method for the non-contact measurement of dynamic torsion in a rotating shaft using magnetostrictive sensors (MsS). The monitoring and detection system has specially configured magnetostrictive signal detectors that include inductive pick-up coils, in which signals corresponding to localized shaft torques are induced. The basic system sensor utilizes either a permanent DC bias magnet positioned adjacent the rotating shaft or applies a residual magnetic field to the shaft. The techniques described in conjunction with the system are particularly advantageous for on-line monitoring of loaded rotating shafts that are integral parts of power trains, by providing a low-cost and a long-term sensor for acquiring dynamic data of the shaft portion of the machinery system being monitored and/or controlled.

US Patent:

6815948, Nov 9, 2004

Filed:

Sep 30, 2003

Appl. No.:

10/673649

Inventors:

Hegeon Kwun - san Antonio TX
Sang-Young Kim - San Antonio TX
Kyoichi Asano - Tokyo, JP

Assignee:

The Tokyo Electric Power Company, Inc. - Tokyo

International Classification:

G01N 2782

US Classification:

324238

Abstract:

A method and apparatus for the nondestructive detecting of tension wires in a concrete pole from a single test location without requiring scanning along the length of the pole and without requiring direct contact to the wires. The method and apparatus utilize longitudinal guided waves in tension wires that are generated and detected based on the magnetostrictive sensor principle. The detected signals from broken tension wires and from the ends of concrete pole are analyzed for the number and locations of broken wires.