ANALYSIS OF THE PASSIVE MECHANICAL BEHAVIOR OF TAENIAE COLI: EXPERIMENTAL AND NUMERICAL APPROACH

The constitutive analysis of gastrointestinal tissues represents a fundamental aspect for the biomechanical investigation of gastrointestinal structures and organs by using computational methods. This approach makes it possible to obtain an accurate and extensive set of results, also offering the possibility to evaluate the interaction with surgical devices. The constitutive analysis of taeniae coli tissue is performed by a multi-disciplinary approach that requires the cooperation between medical, experimental and computational competences, as common practice in biological tissues mechanics. The analysis of taeniae coli histology suggests the assumption of a transversally isotropic scheme, because of the orientation of muscular fibres along a preferential direction. Mechanical tests are designed and planned in consideration of the mentioned structural conformation, considering tensile tests imposed according to different loading directions. The results from histological and experimental investigations lead to the definition of a constitutive model in the framework of fibre-reinforced hyperelastic materials. The constitutive parameters are evaluated by the comparative analysis between experimental and numerical results by means of a minimization of their discrepancy. The reliability of the constitutive formulation and parameters is assessed by the analysis of additional experimental data and the evaluation of satisfaction of thermo-mechanics requirements about material stability.