Abstract: A flaw detection system using acoustic Doppler effect for detecting flaws in a medium wherein there is relative motion between the medium and system includes a transducer, spaced from the medium to be inspected, for introducing to and sensing from the medium an acoustic signal that propagates in the medium at a predetermined frequency; and a detector, responsive to the sensed propagating acoustic signal, for detecting in the sensed acoustic signal the Doppler shifted frequency representative of a flaw in the medium.

Abstract: Detecting a defect in the sample is accomplished by photoacousticly exciting acoustic longitudinal, surface Rayleigh, and shear waves at a first point on a near surface of a sample; photoacoustically detecting acoustic waves at a second point spaced from the excitation first point for intercepting shear waves reflected from the far surface of the sample at approximately the angle of maximum shear wave propagation; and detecting the energy level of the intercepted reflected shear waves representative of the flaw in the sample.

Abstract: A tuned wave phased array includes a plurality of spaced transmitter elements, a signal generator that produces an activation signal for activating the transmitter elements to transmit a guided wave in an associated medium and a delay circuit for sequentially delaying the activation of at least one of the transmitter elements for creating constructive interference of a selected mode of the wave propagating in the medium, thereby boosting the selected mode of the wave.

Abstract: A flaw detection system using acoustic Doppler effect for detecting flaws in a medium wherein there is relative motion between the medium and system includes a transducer, spaced from the medium to be inspected, for introducing to and sensing from the medium an acoustic signal that propagates in the medium at a predetermined frequency; and a detector, responsive to the sensed propagating acoustic signal, for detecting in the sensed acoustic signal the Doppler shifted frequency representative of a flaw in the medium.

Abstract: A building construction and method using tension support members includes a support structure for bearing a compressive load; a support beam borne by the structure; at least one enclosure cell and at least one tension member for suspending an enclosure cell from the support beam.

Abstract: Detecting a defect in the sample is accomplished by photoacousticly exciting acoustic longitudinal, surface Rayleigh, and shear waves at a first point on a near surface of a sample; photoacoustically detecting acoustic waves at a second point spaced from the excitation first point for intercepting shear waves reflected from the far surface of the sample at approximately the angle of maximum shear wave propagation; and detecting the energy level of the intercepted reflected shear waves representative of the flaw in the sample.

Abstract: An ultrasonic defect detection system includes a steered beam transmitter for directing an ultrasonic beam through the front face to the back face of a specimen; a sensor device for sensing the location on the front face of the near shadow of a defect from the beam reflected from the back face before the defect and the far shadow of the defect from the beam reflected from the back face after the defect; and an arithmetic circuit responsive to the location of the shadows on the front face for determining the distance between the transmitter and the near and far boundary of the near shadow and at least the near boundary of the far shadow for calculating the location and/or the size and/or the orientation of the defect.

Abstract: A method and system of locating discontinuities, measuring distances, locating unknown sources, and measuring the thickness of multimode dispersive medium includes sensing a multimode dispersive acoustic guided wave and frequency decomposing that wave using spectral temporal analysis; selecting a frequency which identifies a group delay of the guided wave for each mode occurring at that frequency; selecting a mode from the group delays of the selected mode, determining the group velocity from the dispersion curves and computing the desired parameter.

Abstract: A flaw detection system using acoustic Doppler effect for detecting flaws in a medium wherein there is relative motion between the medium and system includes a transducer, spaced from the medium to be inspected, for introducing to and sensing from the medium an acoustic signal that propagates in the medium at a predetermined frequency; and a detector, responsive to the sensed propagating acoustic signal, for detecting in the sensed acoustic signal the Doppler shifted frequency representative of a flaw in the medium.

Abstract: A flaw detection system using acoustic Doppler effect for detecting flaws in a medium wherein there is relative motion between the medium and system includes a transducer, spaced from the medium to be inspected, for introducing to and sensing from the medium an acoustic signal that propagates in the medium at a predetermined frequency; and a detector, responsive to the sensed propagating acoustic signal, for detecting in the sensed acoustic signal the Doppler shifted frequency representative of a flaw in the medium.

Abstract: A flaw detection system using acoustic Doppler effect for detecting flaws in a medium wherein there is relative motion between the medium and system includes a transducer, spaced from the medium to be inspected, for introducing to and sensing from the medium an acoustic signal that propagates in the medium at a predetermined frequency; and a detector, responsive to the sensed propagating acoustic signal, for detecting in the sensed acoustic signal the Doppler shifted frequency representative of a flaw in the medium.

Abstract: A flaw detection system using acoustic Doppler effect for detecting flaws in a medium wherein there is relative motion between the medium and system includes a transducer, spaced from the medium to be inspected, for introducing to and sensing from the medium an acoustic signal that propagates in the medium at a predetermined frequency; and a detector, responsive to the sensed propagating acoustic signal, for detecting in the sensed acoustic signal the Doppler shifted frequency representative of a flaw in the medium.

Abstract: A synthetic phase tuned multi-mode acoustic guided wave system and method activates at least one of a plurality of elements as a receiver or a transmitter and at least two of the elements as transmitters or receivers, respectively, and sequentially excites each of the transmitter elements for creating a train of acoustic guided waves which includes a selected mode, and shifts the acoustic guided waves of the selected mode sensed by the receivers by a period which is a function of the phase velocity of the selected mode and sums them to reinforce the selected mode.