ASA 125th Meeting Ottawa 1993 May

3pPA7. Temporal response of an elastic sphere kidney stone and gallstone model to pulsatile plane wave excitation.

Robert C. Waag

Timothy J. Case

Dept. of Elec. Eng., Univ. of Rochester, Rochester, NY 14627

An elastic sphere has been employed to model kidney stones and gallstones. Temporal harmonic amplitudes of the stress tensor components in the sphere were expressed in a spherical coordinate system using acoustic displacements found from an orthogonal function series with coefficients determined by boundary conditions. Corresponding temporal responses were then obtained via Fourier transformation and principal stresses as well as stress combinations proposed by von Misses and Tresca for the onset of inelastic behavior were calculated. Cross-sectional and three-dimensional displays of these stresses in the sphere at sequential instants of time shows the temporal growth and reverberant decay of the stress field resulting from an incident pulsatile plane wave. The model may be employed to study the influence of the incident waveform shape on the distribution of induced stress in kidney stones and gallstones.