ASA 127th Meeting M.I.T. 1994 June 6-10

3aPA5. A modified T-matrix approach for scatterers with mixed boundary conditions or concavities.

Vasundara V. Varadan

Yong Woo Kim

Vijay K. Varadan

Res. Ctr. for the Eng. of Electron. and Acoust. Mater., Dept. of Eng. Sci. and Mech., Penn State Univ., University Park, PA 16802

Many scattering problems involve specification of different types of boundary conditions on different parts of the surface of the same scatterer or the geometry of the scatterer may involve concavities. Both these problems are difficult to model using available methods. The applications of such problems are however many---debonded fibers in fiber reinforced composites, partially coated inclusions in engineered coatings, to name just two. A modification of the usual T-matrix approach is proposed by constructing a mathematical surface which partially includes the actual surface of the scatterer. The integral representations for the fields for the two regions---the actual scatterer volume and the volume enclosed by the extended surface are simultaneously solved. A general formulation is presented with numerical results for P- and S-wave scattering by partially debonded fibers in an elastic matrix. [sup a)]Present address: Samsung Electronics, Suwon, Korea.