Reiner Wilhelms-Tricarico
Methods for modeling of
soft-tissue speech articulators
Abstract:The soft tissues of tongue and lips can be approximated as continua. This gives a foundation for applying the finite element method to simulate these structures in a biomechanical speech production model. Movements and deformations of these organs can then be computed as the solutions of a non-linear second order system of ordinary differential equations which is obtained from a finite element approximation of an energy rate equation. The muscle fibers in the organs are represented as direction specifying fields. In each muscle type pure tensil active stress contributions are produced. Three types of boundaries are considered: boundaries where impact and sliding can take place, such as the hard palate; boundaries of where a body surface can only move on another fixed surface; and attachments to moving rigid structures. A method for maintaining an incompressibility condition as a geometric constraint, during the simulation is presented in detail. The implementation of the simulation procedures as a C++ class library is in progress. A partial model of a tongue with eight muscles was completed and tested.