ASA 124th Meeting New Orleans 1992 October

3pSP8. Finite element tongue model---Algorithms.

Reiner Wilhelms

ATR International, Kyoto, Japan

Chao-Min Wu

Biomed. Eng. Ctr., Ohio State Univ., Columbus, OH 43210-1002

An algorithm has been implemented that can solve the equations of motion of an incompressible tissue that is able of active contractions in multiple directions. This algorithm is used for the construction of a three-dimensional computational model of the human tongue. In the model, muscle fibers are represented as vector fields in a reference configuration, and the equations of motion are formulated in that reference configuration. The finite element method is applied for the numerical approximation, using 8 node or 27 node elements (for linear or quadratic interpolation). The muscular stresses are computed with a simple model of muscle tissue, in which the active stress depends on activation parameters and on the elongation in the direction of the muscle fibers and its rate of change. The activation parameters change the constitutive equations of the tissue. Incompressibility during the deformation is maintained by using a reduced stress calculation in which the components of the stress tensor, which cause nonisocoric deformation, are subtracted from the stress tensor. [Work supported by the Whitaker Foundation.]