Abstract: To obtain a measure of the size of a spot weld nugget, the weld is scanned with an ultrasonic beam of about 20 megahertz frequency. The ultrasonic signal transmitted through the part is analyzed to determine the presence of the part and the presence of a weld. The detected signal is gated to pass a portion of the signal which has been multiply reflected through the weld region to a bandpass filter which passes frequencies that are selectively attenuated by a weld nugget much more than the surface bond or stick zone surrounding the nugget so that the energy content of the filtered signal is used to determine the presence of nugget material at any point during the scan. A chart recorder controlled according to the energy content of the filtered signal produces a characteristic signature for each weld which distinguishes between the extent of the stick zone and the nugget of each weld so that the weld nugget size is readily determined.

Abstract: A non-destructive evaluation technique particularly suited for in situ testing utilizes significant changes in internal friction damping (IFD) as an indicating factor. A baseline for the specific damping capacity of an object is determined and a tolerance range is established from the baseline. Measurements of the specific damping capacity are periodically made and checked to see if they are within the tolerance range. Unexpected changes in specific damping capacity indicate the presence of an incipient flaw in the object. The evaluation technique can also be used to locate flaws, monitor crack growth and predict useful life. Apparatus for measuring specific damping capacity is also disclosed.

Abstract: A method for flaw detection in solder joints, especially on printed circuit (PC) boards, by means of the application of sonic and ultrasonic energy, with or without an electrical current therewith, upstream of the solder joint and comparison of these acoustic and electrical inputs to their respective modulated outputs downstream of the joint.

Abstract: A device for inspecting spot welds which comprises a probe for receiving a reflected wave from an inspection material, a weld state display unit for displaying a waveform, a pulse interval and a number of pulses of the reflected wave, and a wave guide connected to an end portion of the probe, for guiding the reflected wave from the inspection material to the probe. The wave guide has an ultrasonic wave propagating section in the form of a cylinder and an internal ultrasonic wave absorbing section obtained by filling an inside hole of the cylinder with an ultrasonic wave absorbing material, the ultrasonic wave propagating section being so dimensioned that the length of an ultrasonic wave propagating path is within the range calculated from the following equation:L=n.lambda..+-.0.2.lambda.where n is an integer value, .lambda. is the wavelength (mm) of an ultrasonic wave, and L is the length (mm) of the ultrasonic wave propagating path.

Abstract: Disclosed is a means and method for evaluating a bond between first and second structures bonded together by an intermediate layer of adhesive. Means are provided for transmitting a pulse of ultrasonic wave energy into the bonded structures whereby a first reflected pulse may be reflected from a first surface of the first structure, a second reflected pulse reflected from the layer of adhesive, and a third pulse possibly reflected from the surface of the second structure adjacent the adhesive layer. Circuit means are provided for sensing the first, second, and third reflected pulses and for providing an indication of the quality of the bond by comparing the amplitudes of the reflected pulses and determining if the ratios lie within predetermined ranges.

Abstract: An apparatus for non-destructively testing concrete comprises a tri-wheel platform having a transducer mounted adjacent each wheel and mechanically coupled to the concrete to be responsive to vibration. An aperture is formed in the center of the platform equispaced from the three transducers. Vibrations are imparted to the concrete that emanate outwardly toward the transducers by manually striking the concrete through the center aperture with a rubber tipped impact rod. The transducers generate electrical signals responsive to the amplitudes of detected vibrations which are a function of the structural continuity of the concrete. Electronic circuitry monitors the outputs of the transducers and makes comparisons of the signals to determine whether a flaw exists in the concrete within the region bounded by the three transducers.

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.

Abstract: A system for inspection of adhesively bonded structures utilizing a piezoelectric transmitting transducer for transmitting a fixed frequency tone burst, e.g., 25 KHz, at a predetermined repetition rate, e.g., 100 Hz, into a part being tested and including a piezoelectric receiving transducer also coupled to the part for providing in a receiver circuit an audible output which permits the operator to distinguish amplitude variations of the 100 Hz repetition rate signal representative of the presence of an unbonded area.

Abstract: Disclosed is an apparatus and method for evaluating a bond between first and second structures bonded together by an intermediate layer of adhesive. Apparatus is provided for transmitting a pulse of ultrasonic wave energy that has a duration at least as short as 1.5 wave cycles into the bonded structures whereby a first reflected pulse may be reflected from a first surface of the first structure, a second reflected pulse reflected from the layer of adhesive, and a third pulse possibly reflected from the surface of the second structure adjacent the adhesive layer. Circuits are provided for sensing the first, second, and third reflected pulses and for providing an indication of the quality of the bond by comparing the amplitudes of the reflected pulses and determining if the ratios lie within predetermined ranges.

Abstract: A weld inspection system uses fluoroscopic flaw detection particularly sensitive to volumetric type weld flaws and ultrasonic flaw detection particularly sensitive to planar type weld flaws. Both inspections are performed simultaneously throughout the pipe length. Each system marks the pipe with a distinguishing mark to identify the location of the flaw detected by that system. The fluoroscopic system is a high resolution system, the ultrasonic system avoids detection of minor non-rejectable variation in weld bead geometry and is calibrated to a desired sensitivity level.