Abstract: There is provided an inspection device for the detection of flaws in a component. The inspection device comprises a first linear array of conductors and a second linear array of conductors that is generally parallel and orthogonal to the first linear array of conductors. The electric currents flowing through the first and second arrays create a magnetic field directed into the component that induces unidirectional eddy currents in the component. The unidirectional eddy currents may be rotated through 360 degrees by varying the amplitude and offsetting the phase of the electric currents flowing through the first and second arrays of conductors. When the unidirectional eddy currents encounter a flaw in the component, magnetic field signals in a Z vector are generated. The inspection device comprises a pickup sensor that detects the magnetic field signals to provide an output signal that is processed to determine parameters of the detected flaw.

Abstract: A device for detecting hidden cracks in a structure includes a hand-held probe which is moved over the surface of the structure. The probe is connected to a computer terminal which also has connected thereto a monitor and a keyboard. Changes in the eddy currents in the underlying structure generates impedance changes in the coils of the probe. The resulting voltage values produce an image of the underlying structure and any cracks therein on the computer monitor. The system utilizes a number of procedures to compensate for liftoff problems, imbalance between coil channels, and differences in impedance reference values.

Abstract: A fiber optic cable extends into the housing of an induction heater and has a sensing end positioned to confront a part being heated. Infrared radiation from the part is transmitted by the cable to a transducer. The transducer converts the infrared energy into an electrical signal that is used by a control circuit to control the heating operation. The control circuit has an internal electronic timer that is used in normal operation and to detect certain failure conditions. In normal operation, electromagnetic pulses are provided to the heater at a predetermined power level until the part reaches a predetermined temperature. Then the control circuit adjusts the power level to hold the part at the temperature for a brief holding period. The timer is used by the control circuit to detect failure to reach a desired temperature after a maximum delay and to detect dropping of the temperature below a minimum level during the holding period. The control circuit also detects overheating of the workpiece.

Abstract: An improved ultrasonic inspection system is provided which allows ultrasonic inspection to be performed using either of two ultrasonic frequencies and which also provides improved system sensitivity and dynamic range. In operation, the system produces two signals, one an amplified receive transducer signal and the other an attenuated receive transducer signal. Each signal is converted into a logarithmic representation. The two logarithmic representations are selectively provided to a read-only memory, which operates to output a signal corresponding to the receive transducer signal. Means are also provided which allows the system to use either of two ultrasonic frequencies.

Abstract: An ultrasonic transducer for generating an apodized beam of ultrasonic energy. A piezoelectric crystal element mounted in a housing generates on ultrasonic signal when electrically energized. A tungsten-epoxy layer mounted on the outer surface of the piezoelectric crystal element has a greater thickness at the periphery of the element than at the center, thus yielding an outwardly concave surface. The tungsten-epoxy layer provides a more uniform beam pattern.

Abstract: An ultrasonic water jet having first and second housing members. The first housing member includes an interior exponentially shaped duct and a plurality of water inlets equiangularly displaced and circumferentially disposed about the central axis of the exponentially shaped duct for cleansing a face of the quarter wave matching plate which is bonded to a ceramic disk transducer which forms part of a hermetically sealed assembly. This transducer assembly is both water tight and electromagnetically shielded.

Abstract: A system for measuring the cladding thickness on aluminum sheets which includes a cylindrical probe holder with four evenly spaced contact points surrounding a low temperature coefficient torroidal ferrite core which provides a signal to an aluminum cladding thickness signal processing circuit comprising a crystal oscillator, low drift detector, and push button calibration instrument portion thereby enabling drift free repeatable measurements.

Abstract: An induction heater probe for use with stud mounted hot melt fasteners, the induction heater probe having an outer ferrite cup core portion and an inner hollow cylindrically shaped ferrite core portion with an aperture configured to receive the stud portion of a hot melt fastener. Induction windings surround the inner cylindrical core portion, the housing supporting the ferrite cup core portion including an adjustment screw for limiting the entry of the stud portion of the fastener into the core hole in the inner hollowed cylinder-shaped ferrite core portion of the pot core in the induction heater probe. The pot core ferrite material provides a low reluctance path for the magnetic field lines thereby shielding the stud portion of the hot melt fastener. A coupling coil surrounding the inner hollow cylindrical-shaped ferrite core portion is excited with 35 kHz energy for a period of about ten seconds thereby heating the fastener to approximately 600.degree. F.

Abstract: A system for inspection of bonded structures utilizing an electromagnetic transmitting transducer for transmitting at an audio frequency which is varied linearly from 10.sup.2 to 10.sup.4 Hz with a repetition rate which is variable from 2 Hz to 50 Hz into a part being tested and including a condenser microphone also coupled to the part for providing in a receiver circuit an audible output which enables the operator to distinguish a change in the audio spectrum representative of a disbond condition.