Real-time muscle deformation via decoupled modeling of solid and muscle fiber mechanics.

This paper presents a novel approach for simulating 3D muscle deformations with complex architectures. The approach consists in choosing the best model formulation in terms of computation cost and accuracy, that mixes a volumetric-tissue model based on finite element method (3D FEM), a muscle fiber model (Hill contractile 1D element) and a membrane model accounting for aponeurosis tissue (2D FEM). The separate models are mechanically binded using barycentric embeddings. Our approach allows the computation of several fiber directions in one coarse finite element, and thus, strongly decreases the required finite element resolution to predict muscle deformation during contraction. Using surface registration, fibers tracks of specific architecture can be transferred from a template to subject morphology, and then simulated. As a case study, three different architectures are simulated and compared to their equivalent one dimensional Hill wire model simulations.

3D volumetric muscle modeling for real-time deformation analysis with FEM.

Computer simulation is promising numerical tool to study muscle volumetric deformations. However, most models are facing very long computation time and thus are based on simplified wire Hill muscle model. The purpose of this study is to develop a real-time three-dimensional biomechanical model of volumetric muscle based on modified Hill model for the active stress which is controlled from EMG recordings. Finite element model is used to estimate the passive behavior of the muscle and tendons during contraction. We demonstrate that this 3D model implementation is very cost effective with respect to the computation time and the simulation gives good results compared to real measured data. Thus, this effective implementation will allow implementing much more complex and realistic models considering the muscle as volumetric continuum, with moderate computation time.