Abstract: A method for detecting residual stress induced by cold expansion (Cx) (Cx stress) at a hole in a structure. Two transducer pairs transmit and receive ultrasonic waves into the structure in a pitch-catch configuration along two first paths parallel to a tangent of the hole. The two paths are at different distances from the hole. Both transducer pairs are arranged such that their incident angle into the structure provides longitudinal critically refracted (LCR) waves within the structure. Time-of-flight (ToF) measurements of the LCR waves along the first path and the second path are the basis of acoustoelasticity calculations that determine if Cx stress is present at the hole.

Abstract: A method of in situ measurement of an acoustoelastic constant (L) of a railway rail, using an ultrasonic wedge sensor to measure a stress-free (unloaded) time-of-flight (t0) in the vertical direction of the rail. Next, a vertical load of known load value is applied to the rail. While the vertical load is applied, the ultrasonic wedge sensor is used to measure a stressed time-of-flight value. The difference between the stress-free and the stressed time-of-flight is calculated to obtain a time-of-flight difference value (?t). Based on the load value, the stress-free time-of-flight value, and the time-of-flight difference value, the acoustoelastic constant, L, may be calculated. The wedge sensor may be further used to measure the (stressed) horizontal time of flight, and a time-of-flight difference value in the horizontal direction may be used to measure longitudinal stress.

Abstract: A guided wave probe for use in guided wave testing of plate structures. The probe comprises a cup having a flat or nearly flat bottom, and a guided wave sensor, such as a magnetostrictive sensor, placed in the bottom of the cup. The sensor and/or cup are coupled to the plate structure, such that ultrasonic energy from the sensor is transmitted to the cup and the plate surface. The sensor is incrementally rotated in the cup, and sensor data is acquired at each incremental position.

Abstract: Methods of testing the material of a metal object made by additive manufacturing. An electromagnetic acoustic transducer (EMAT) is used to transmit long duration acoustic signals into the object, and to receive response signals representing resonance of acoustic waves within the material. At least one resonance peak is identified and used to determine attenuation and/or wave velocity. These values can then be used to determine material properties, such as porosity, Shear Modulus, Young's Modulus, or Poisson's Ratio.

Abstract: Methods of testing the material of a metal object made by additive manufacturing. An electromagnetic acoustic transducer (EMAT) is used to transmit long duration acoustic signals into the object, and to receive response signals representing resonance of acoustic waves within the material. At least one resonance peak is identified and used to determine attenuation and/or wave velocity. These values can then be used to determine material properties, such as porosity, Shear Modulus, Young's Modulus, or Poisson's Ratio.

Abstract: A guided wave probe for use in guided wave testing of plate structures. The probe comprises a cup having a flat or nearly flat bottom, and a guided wave sensor, such as a magnetostrictive sensor, placed in the bottom of the cup. The sensor and/or cup are coupled to the plate structure, such that ultrasonic energy from the sensor is transmitted to the cup and the plate surface. The sensor is incrementally rotated in the cup, and sensor data is acquired at each incremental position.

Abstract: A flexible printed circuit board (PCB) magnetostrictive (MS) sensor comprising a first direct current (DC) bias PCB layer comprising a first plurality of conductive traces, a first alternating current (AC) PCB layer disposed on the first DC bias PCB layer, the first AC PCB layer comprising a first AC coil, a pocket PCB layer disposed on the first AC PCB layer, the pocket PCB layer to receive a strip of MS material, a second AC PCB layer disposed on the pocket PCB layer, the second AC PCB layer comprising a second AC coil, and a second DC bias PCB layer disposed on the second AC PCB layer, the second DC bias PCB layer comprising a second plurality of conductive traces. The traces from the first plurality of conductive traces are electrically coupled to traces from the second plurality of conductive traces.

Abstract: An ultrasonic probe that uses the magnetostrictive effect to generate and detect a surface-coupled guided wave for the purpose of inspecting a thick-walled structure for surface defects. A transmitter sensor and a receiver sensor are especially designed to generate and detect short wavelengths that will couple to only one surface of the plate.

Abstract: A flexible printed circuit board (PCB) magnetostrictive (MS) sensor comprising a first direct current (DC) bias PCB layer comprising a first plurality of conductive traces, a first alternating current (AC) PCB layer disposed on the first DC bias PCB layer, the first AC PCB layer comprising a first AC coil, a pocket PCB layer disposed on the first AC PCB layer, the pocket PCB layer to receive a strip of MS material, a second AC PCB layer disposed on the pocket PCB layer, the second AC PCB layer comprising a second AC coil, and a second DC bias PCB layer disposed on the second AC PCB layer, the second DC bias PCB layer comprising a second plurality of conductive traces. The traces from the first plurality of conductive traces are electrically coupled to traces from the second plurality of conductive traces.

Abstract: A method of testing for defects in the bottom of an above ground storage tank, the tank bottom having a lip extending outwardly from the tank wall around the circumference of the tank. A special magnetostrictive sensor is designed to be placed on this lip. The sensor is placed over a strip of magnetostrictive material, which generally conforms in length and width to the bottom of the probe, with a couplant being applied between the strip and the lip surface. The sensor is then operated in pulse echo mode to receive signals from defects in the bottom of the tank. It is incrementally moved around the circumference of the tank.

Abstract: An ultrasonic probe that uses the magnetostrictive effect to generate and detect a surface-coupled guided wave for the purpose of inspecting a thick-walled structure for surface defects. A transmitter probe and a receiver probe are especially designed to generate and detect short wavelengths that will couple to only one surface of the plate.

Abstract: A method of testing for defects in the bottom of an above ground storage tank, the tank bottom having a lip extending outwardly from the tank wall around the circumference of the tank. A special magnetostrictive sensor is designed to be placed on this lip. The sensor is placed over a strip of magnetostrictive material, which generally conforms in length and width to the bottom of the probe, with a couplant being applied between the strip and the lip surface. The sensor is then operated in pulse echo mode to receive signals from defects in the bottom of the tank. It is incrementally moved around the circumference of the tank.