An inhomogeneous mechanical replica of the vocal folds.
Xavier Pelorson, Annemie van Hirtum · The Journal of the Acoustical Society of America · 2009
In parallel with theoretical modeling, in-vitro mechanical replicas of the human larynx have become very popular in the speech science community. These experimental devices are indeed extremely useful in order to evaluate the relevance and the accuracy of physical models of speech production. In this paper, a new mechanical model of the vocal folds is presented. It consists of a self-oscillating structure made of various layers with different mechanical properties (silicone, rubber, and/or liquid). The elasticity of the deeper layer can be controlled by stress/strain system. Although very simplified, such mechanical model is intended to replicate an inhomogeneous structure comparable to the human vocal folds one. The mechanical replica is then mounted on a air reservoir whose pressure can be controlled. The pressure upstream and downstream of the replica are measured together with the mechanical displacement of the artificial folds, thanks to a laser device. Typical examples of measurements will be presented for various alimentation pressures and elasticity conditions. The relevance of the observed effects with respect to human phonation and the possibility to explain them using simple mass-spring mechanical models will be discussed.