INTRODUCI10N Scattering characteristics have been calculated for a spherical inclusion with partially de bonded interphase conditions. Three scattering characteristics of the scattered field have been selected for investigation: 1) the frequency response at a fixed point, 2) the scattered field at a fixed frequency along an observation line, and 3) the radiation pattern. The compliant interphase between the inclusion and the surrounding elastic matrix has been modeled by a layer of distributed

more »

... prings which offers resistance to relative displacements in the two tangent and the normal directions. Two basic assumptions are made for the spring model of the interphase: 1) The springs are linear, and 2) The interphase is very thin so that the effect of inertia of the interphase can be neglected. These assumptions are acceptable in the low frequency range. The partial debonding of the interphase is modeled by setting the spring constants (defined per unit area) equal to zero along part of the interphase. The method of solution is based on the 3D elastodynamic boundary integral equation method. The treatment of the interphase and the solution strategy have been discussed in detail in our previous paper[1]; so we omit the details here. The spring model has been reviewed in some recent articles by Baik and Thompson[2], and Martin[3]. SUMMARY OF TIIE FORMULATION The integral representation for the exterior displacement field can be expressed as XED, (I) where S is the interphase boundary at the matrix side and Uij is the fundamental solution for 3D time-harmonic elastodynamics. The boundary integral equation for the exterior matrix may subsequently be obtained as