Modelling the passive mechanical properties of arteries

Abstract: This thesis concerns the modelling of passive mechanical properties of arteries. An artery is characterised by large nonlinear deformation, anisotropy and incompressibility. In addition, it is subjected to a residual stress when the applied load is removed. All this combined makes it complex to derive appropriate mechanical models. Even though, models of this kind are highly desirable since they could help to diagnose diseases and indicate if there is a need for surgical intervention.The mechanical model presented in this thesis satisfies most of the important mechanical properties of a passive artery. It is a nonlinear, orthotropic and incompressible model, which accounts for the residual stress by defining a hypothetical, stress free reference state. The model is able to give a good fit between the model pressure and the measured pressure, while having a relatively small number of unknown model parameters.The model is used for in-vivo parameter identification and stress estimation on an abdominal aorta from a young healthy male. The measured data is a limited pressureradius set, typically of the type obtained in clinical practice. Three material parameters and four parameters associated with the residual stress are identified by a minimization process. The results shows that specific material parameters, and in particular the residual stress, can be obtained for an individual, using in-vivo measurable data only.