THEORY OF THE ACOUSTIC SIGNATURE OF TOPOLOGICAL AND MORPHOLOGICAL DEFECTS IN SIC POROUS SIC LAMINATED CERAMICS/

The sensitivity of acoustic techniques to topological and/or morpholog ical variations in SiC/porous SiC laminated ceramics is studied within the transfer matrix formalism. To implement this theoretical formalis m, the mechanical properties of the SIC porous layers are calculated u sing the effective medium approximation of Kuster and Toksoz [Geophys. 39, 587 (1974)]. We show that topological defects have a stronger aco ustic signature than morphological defects. Also, we observe that ther e are particular frequencies at which the defects do not present any a coustic signature. (C) 1997 American Institute of Physics.