Accession Number : ADA300879

Title :   Acousto-Ultrasonic Input-Output Characterization of Unidirectional Fiber Composite Plate by SH Waves.

Descriptive Note : Final contractor rept.,

Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF MECHANICAL ENGINEERING

Personal Author(s) : Williams, James H., Jr. ; Liao, Peter

PDF Url : ADA300879

Report Date : AUG 1987

Pagination or Media Count : 50

Abstract : A unidirectional fiberglass epoxy composite plate specimen is modelled as a homogeneous transversely isotropic continuum plate medium. Acousto-ultrasonic non-contact input-output characterization by tracing SH waves in the continuum is studied theoretically with a transmitting and a receiving transducer located on the same face of the plate. The single reflection problem at a stress-free plane boundary in a semi-infinite transversely isotropic medium whose isotropic plane is parallel to the plane boundary is analyzed first. It is found that an incident SH wave results in a reflected SH wave only; the amplitude ratio of the reflected SH wave to the incident SH wave is negative one; and the angle of reflection of the reflected SH wave is equal to the angle of incidence of the incident SH wave. The balance in energy flux normal to the plane boundary is also checked. The delay time is calculated as if the SH waves were propagating in an infinite half space. It is found that the directional dependence of the phase velocity of the SH waves travelling in the transversely isotropic medium has a significant effect on the delay time, as opposed to the directional independence of the phase velocity of the SH wave travelling in an isotropic medium.

Descriptors :   *ACOUSTIC WAVES, *FIBER REINFORCED COMPOSITES, *AEROSPACE CRAFT, *EPOXY COMPOSITES, FIBERGLASS, NONDESTRUCTIVE TESTING, DISPLACEMENT, VOLTAGE, COMPOSITE STRUCTURES, REFLECTION, CERAMIC MATERIALS, PLATES, ISOTROPISM, SHEAR STRESSES, TRANSDUCERS, AMPLITUDE, TRAVELING WAVES, ULTRASONIC TESTS, STRESS WAVES, ELASTIC WAVES, PHASE VELOCITY.

Subject Categories : Laminates and Composite Materials
      Acoustics
      Research and Experimental Aircraft

Distribution Statement : APPROVED FOR PUBLIC RELEASE