From muscle fibre to tissue - experiment, modelling and simulation at micro, meso and makro scale

本项目涉及骨骼肌组织的复杂变形状态的分析，其结果将被整合在一个数值多尺度建模方法。该项目的基本目标是确定细胞外基质（ECM）的机械行为，并根据ECM的定量和/或结构变化预测变化。然而，这种知识具有很高的医学和社会经济重要性，但基于以前的分析方法，无法获得。为了推进这一领域的研究，本项目结合了两个专业领域：微系统技术和固体力学。这种独特的组合提供了一种全新的创新方法，并能够开发新的方法，以便从实验和数值的角度分析骨骼肌组织。因此，该项目提供了不同尺寸尺度的广泛实验分析。在第一步中，我们分别对单根肌纤维和肌纤维段进行微尺度（10-90 µm）轴向拉伸和轴向/横向压缩实验。此外，在中尺度（0.1 -1 mm），我们专注于压缩和剪切压缩测试应用于从肌肉束切除的立方体。最后，从肌肉组织中切除的立方体将在宏观尺度（1-24 mm）下进行测试。为了进行这样的实验，需要开发微观和中尺度的特殊装置。他们的主要组成部分将是微型技术的平行夹具。在这样做时，可以加载通过超短脉冲激光从肌束切除的单个肌纤维或立方体，并且可以测量力、位移和变形。宏观尺度的实验将使用众所周知的实验方法来完成。基于这些多尺度实验，通过逆有限元方法，我们建立了一个三步识别过程，允许确定ECM的力学行为。最后，植根于这些研究结果的多尺度建模方法及其验证计划。

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 within the project 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.