Investigation of LS-DYNA Modeling for Active Muscle Tissue

This study is aimed at investigating and comparing one-dimensional and three-dimensional finite element models of active muscle tissue. Skeletal muscle is a very complicated biological structure to model due to its non- homogeneous and non-linear material properties as well as its complex geometry. Additionally, forces generated from muscle activation are directly related to the muscle length and contraction velocity. Finite element discrete Hill-based elements are largely used to simulate muscles in both passive and active states. There are, however, several shortfalls to utilizing one- dimensional elements, such as the impossibility to represent muscle physical mass and complex lines of action. Additionally, the use of one-dimensional elements restricts muscle insertion sites to a limited number of nodes causing unrealistic loading distributions. These limitations are partially solved with a three-dimensional solid muscle model, where discrete Hill-based elements are combined in series and parallel to solid elements possessing hypo-elastic material properties. Despite some instability, the model was concluded to be an improvement over purely one-dimensional muscle models