From the muscle fibre to muscle tissue – experiments, modelling and simulation at micro, meso, and macro scale
The present project deals with the analysis of complex deformation states of skeletal muscle tissue whose results will be integrated in a numerical multi-scale modelling approach. The essential aim is the determination of the mechanical behaviour of the extracellular matrix (ECM) and consequently the prediction of changes based on quantitative and/or structural changes of the ECM. This knowledge, however, is of high medical as well as socioeconomical importance but rooted on previous analytical methods it could not be obtained. In order to advance research on this field, the present project combines two areas of expertise: microsystems technology and solid mechanics. This unique combination presents a completely new and innovative approach and enables the development of new methods in order to analyse skeletal muscle tissue from the experimental as well as numerical point of view.
Therefore, this project provides extensive experimental analyses on different size scales. In a first step we apply at micro scale (10-90 μm) axial tension as well as axial/transversal compression experiments on single muscle fibres and muscle fibres segments, respectively. Further, at meso scale (0.1-1 mm), we focus on compression and shear-compression tests applied on cubes excised from muscle fascicles. Finally, cubes resected from muscle tissue will be tested at macro scale (1-24 mm).
In order to perform such experiments special setups at micro and meso scale need to be developed. Their main components will be micro technological parallel grippers. In doing so, single muscle fibres or cubes resected from fascicles by means of ultra-short-pulse laser can be loaded and forces, displacements and deformations can be measured. Experiments at macro scale will be accomplished using well-known experimental methods.
Based on these multi-scale experiments and by means of the inverse finite element method we establish a three-step identification process that allows to determinate the mechanical behaviour of ECM. Finally, rooted on these findings a multi-scale modelling approach and its validation is scheduled.