Accession Number : AD0756385
Title : Ultrasonic Measurement of Phase and Group Velocity Using Continuous Wave Transmission Techniques.
Descriptive Note : Final rept. 24 May-4 Nov 72,
Corporate Author : PANAMETRICS INC WALTHAM MASS
Personal Author(s) : Lynnworth,Lawrence C. ; Papadakis,Emmanuel P. ; Rea,Warren R.
Report Date : JAN 1973
Pagination or Media Count : 56
Abstract : AMMRCCTR-73-2(*composite materials, nondestructive testing), (*halocarbon plastics, ultrasonic radiation), test methods, test equipment, propagation, velocity, attenuationphase, velocity, group velocity, tetrafluoroethylene resins, *ultrasonic testsPhase and group velocities V and U, respectively, were measured in the 100:1 frequency range 50 kHz to 5 MHz using longitudinal and shear ultra-sonic continuous waves in teflon and in a dispersive three-dimensional reinforced composite. A new transmission approach was developed which utilized broadband transducers and a pair of wedges to obtain V BY A DIFFERENTIAL PATH, FIXED FREQUENCY TECHNIQUE, AND TO OBTAIN U by fixed-path, differential frequency technique. The path or frequency was incremented to fit additional whole wavelengths in the path, as indicated by 2 pi phase shifts in a Lissajous pattern. Cross-checks between U AND V confirmed the validity of the approach at least for the two materials investigated. (Author-PL)
Descriptors : (*COMPOSITE MATERIALS, NONDESTRUCTIVE TESTING), (*HALOCARBON PLASTICS, ULTRASONIC RADIATION), TEST METHODS, TEST EQUIPMENT, PROPAGATION, VELOCITY, ATTENUATION
Subject Categories : Laminates and Composite Materials
Test Facilities, Equipment and Methods
Distribution Statement : APPROVED FOR PUBLIC RELEASE