### ASA 124th Meeting New Orleans 1992 October

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

**Reiner Wilhelms
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*ATR International, Kyoto, Japan
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**Chao-Min Wu
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*Biomed. Eng. Ctr., Ohio State Univ., Columbus, OH 43210-1002
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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.]