Abstract: The present invention provides a system and method for detecting changes in the properties of a polymeric material. A frame is hand held against the outside surface of a curved polymeric test specimen, e.g., fluid tank. A transmitting probe attached to the frame emits critically refracted ultrasonic waves that travel longitudinally across the chord of said curved test specimen and are detected by at least one receiving probe attached to the frame. A data processing system measures the travel time of the ultrasonic waves from the transmitting probe to the receiving probe and compares this measured travel time to an expected travel time. Variations in material properties along the penetration path of the ultrasonic waves can be detected from deviation in the measure travel time of the waves from the expected control values. Measuring the temperature of the polymeric specimen allows adjustment of the measured travel time of the waves to account for temperature effects on the polymeric material.

Abstract: The latent stress in both flat and curved materials can be measured using critically refracted longitudinal ultrasonic technique. The system uses a frame to hold a hydraulic piston. The piston is used to apply an adjustable force against the probes. A signal is initiated by a transmitting probe. The signal is angled against the piece under test so as to create a critically refracted wave along the piece. Wedge-shaped probe pads allow placement of the probes on both flat and curved surfaces with various radii and arc lengths. The delay time to receive the wave at a first and second receiving probe is measured. The delay time correlates to a stress in the piece.

Abstract: The latent stress in a material can be measured using critically refracted longitudinal ultrasonic technique. The system uses a frame to hold a hydraulic piston. The piston is used to apply an adjustable force against the probes. A signal is initiated by a first transducer. The signal is angled against the piece under test so as to create a critically refracted wave along the piece. The delay time to receive the wave at a first and second probe is measured. The delay time correlates to a stress in the piece.

Abstract: The latent stress in a material can be measured using critically refracted longitudinal ultrasonic technique. The system uses a frame to hold a hydraulic piston. The piston is used to apply an adjustable force against the probes. A signal is initiated by a first transducer. The signal is angled against the piece under test so as to create a critically refracted wave along the piece. The delay time to receive the wave at a first and second probe is measured. The delay time correlates to a stress in the piece.

Abstract: The latent stress in both flat and curved materials can be measured using critically refracted longitudinal ultrasonic technique. The system uses a frame to hold a hydraulic piston. The piston is used to apply an adjustable force against the probes. A signal is initiated by a transmitting probe. The signal is angled against the piece under test so as to create a critically refracted wave along the piece. Wedge-shaped probe pads allow placement of the probes on both flat and curved surfaces with various radii and arc lengths. The delay time to receive the wave at a first and second receiving probe is measured. The delay time correlates to a stress in the piece.

Abstract: The latent stress in a material can be measured using critically refracted longitudinal ultrasonic technique. The system uses a frame to hold a hydraulic piston. The piston is used to apply an adjustable force against the probes. A signal is initiated by a first transducer. The signal is angled against the piece under test so as to create a critically refracted wave along the piece. The delay time to receive the wave at a first and second probe is measured. The delay time correlates to a stress in the piece.