Federico, SalvatoreHamedzadeh, Amirhossein2018-06-252018-06-252018-06-18Hamedzadeh, A. (2018). Damage and Remodelling in Recruitment-Based Models for Biological Tissues (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/32006http://hdl.handle.net/1880/106780This thesis focuses on the continuum mechanical modelling of soft biological tissues seen as composite material reinforced by collagen fibres. The fibres have a progressive recruitment mechanism, and the tissue can undergo damage or remodelling. The thesis consists of two major parts. In the first part of the thesis, the recruitment and damage of soft tissues are modelled by introducing a rigorous continuum treatment of the fibre seen as a bundle of fibrils. The fibrils have different initial undulation, and this is represented by the means of a recruitment probability distribution. By exploiting the recruitment distribution, we construct a recruitment and damage model, where the fibrils are progressively recruited and damaged. The model is implemented in a Finite Element package and, as an example, the damage of a human Achilles tendon is studied. The Finite Element model is capable of capturing the qualitative behaviour of the tendon under uniaxial tension. The second part of the thesis focusses on the remodelling of biological tissues in the framework of the theory of material uniformity. A constitutive evolution model is introduced, including fibre recruitment and reorientation, and subjected to the entropy inequality, which enforces the Second Principle of Thermodynamics. The model is applied to a numerical example describing a pressurised fibre-reinforced cylinder, roughly representing an artery, and is able to capture the major characteristics of remodelling in arteries, as reported in the literature. To summarise, this thesis provides a framework for modelling of the interaction of fibril recruitment and damage and of whole fibre recruitment and remodelling, and constitutes a promising starting point for a more general model capable of studying the interaction of damage, remodelling and healing.engUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.continuum mechanicsbiological tissuesgrowth and remodellingcollagen fibresEducation--SciencesEngineeringEngineering--Mechanicaldoctoral thesishttp://dx.doi.org/10.11575/PRISM/32006