Micromechanical modelling of skeletal muscles based on the finite element method.

In the present paper, a new concept for the modelling of skeletal muscles is proposed. An important aspect is the fact that the concept is micromechanically motivated. At the level of the contractile muscle fibres we incorporate the behaviour of the smallest possible unit, the so-called sarcomere, also known as microbiological engine. The contractile fibres (active part of the material) are surrounded by a soft tissue network (passive part of the material). One fundamental advantage of micromechanical approaches in general is the fact that the number of material parameters can be noticeably reduced and the remaining parameters can be usually interpreted physically. The chosen modelling strategy enables the efficient transport of the known information about physiological processes in the fibre to the 3D macroscopic level where, e.g. the dependence of muscle contraction on the stimulus rate is studied. The paper closes with investigations of quasistatic as well as dynamic simulation applied on idealised and non-idealised muscle geometries.