Experimental Characterization and Simulation of Layer Interaction in Facial Soft Tissues

Abstract

Abstract. Anatomically detailed modeling of soft tissue structures such as the forehead plays an important role in physics based simulations of facial expressions, for surgery planning, and implant design. We present ultrasound measurements of through-layer tissue deformation in different regions of the forehead. These data were used to determine the local dependence of tissue interaction properties in terms of variations in the relative deformation between individual layers. A physically based finite element model of the forehead is developed and simulations are compared with measurements in order to validate local tissue interaction properties. The model is used for simulation of forehead wrinkling during frontalis muscle contraction.

A biphasic multilayer computational model of human skin

“…The experimental observations were rationalized using several nonlinear material models, as reviewed by Limbert (2017), Benítez and Montáns (2017) and Joodaki and Panzer (2018). Model formulations include the hyperelastic isotropic neo-Hookean (Flynn and McCormack 2008;Delalleau et al 2008) or Arruda-Boyce models (Bischoff et al 2000), the an-isotropic Holzapfel-Gasser-Ogden model (Ní Annaidh et al 2012) and the viscoelastic Rubin-Bodner model (Weickenmeier et al 2014;Wahlsten et al 2019). Most previous approaches model the skin as a single-layer, mono-phasic, incompressible material.…”

Experimental and Numerical Characterization of the Mechanical Masseter Muscle Response During Biting

“…3. Muscle deformation, and crosssectional area changes specifically, are extracted from the ultrasound image sequences using an optical flow tracking algorithm previously presented by Weickenmeier et al [37]. After a manual segmentation of the muscle contour in the first frame of the image sequence, the optical flow algorithm tracks all points in each consecutive frame.…”

“…and depends on the level of activation, sarcomere length (function f f ), and contraction velocity (function f ), the measure of the total number of activated motor units per reference cross-sectional area N a , the total motor unit types n MU , the corresponding fraction of each motor unit q i , and the twitch force of a single motor unit F i t . Weickenmeier et al [28] present the comprehensive numerical implementation of this material model in order to enable the realistic simulation of geometrically complex muscle structures in the face and forehead region [37]. In the present work, material parameters proposed by Weickenmeier et al [28] in Tables 1 and 2 are used in all simulations.…”