Cz En

Research on tissues and body structures and biomaterials

Influence of inhomogeneities on the mechanical behavior of blood vessels - bifurcations

Project description:



Comparison of strain fields in the circular hole surrounding - the planar sample. (Left: FEM Ansys, right: Digital Image Correlation - Istra 4D.)

Tangential stress around the circular hole (r = 3mm) in latex tube (R = 20mm). FEM - Ansys

Uniaxial test of the elastic plate with a hole, use of 2D image correlation (System Q-450)

Rectangular samples cut out from the area of aortic bifurcation are prepared for uni-axial tensile tests. The samples are grouped according to their locations and orientations.

The graph showes the normalized initial modulus of elasticity (at deformation of 12%).

It is considered that the mechanical stress  (or strain) within the walls of large arteries has a significant influence on the generation of atherosclerosis in these places.

Natural vascular branching (or bypass) represents a stress concentrator, which changes stress and strain field in its neighbourhood. The experiment, realized as a combination of an inflation and uniaxial tension, FEM and analytical analysis compare the distribution of these variables depending on the specific geometry of branching.

Timetable of the project: planar sample with circular hole -> tubular sample with different types of boundary conditions on the circular hole -> real vascular branching. Vascular tissue is modeled as nonlinear, hyperelastic, anisotropic and volume incompressible material.

Inflation test of silicone bifurcation. Deformations were recorded using laser scanner.

FEM analysis of the bifurcation (hyperelastic, isotropic incompressible material)

 

the stiffness of the daughter branch

The stiffness of the daughter branch strongly affect distribution of stress/strain. In this case the circumferential stress within arterial wall is simulated by normal stress acting on sides of planar sample with a circular hole. The tubes (branches) with various parameters (Young modulus) are connected to the hole.

MSc. Jakub Kronek Ph.D.doc. Ing. Lukáš Horný Ph.D. Hynek Chlup

Resesrchers:

University Hospital Na KralovskychVinohradech, Srobarova 50, 10034, Prague, Czech

Cooperation:

Literature:

Kronek, J. - Chlup, H. - Hromádka, D. - Žitný, R.: Are cells orientations inside aortic bifurcation usable indicator of macroscopic mechanical properties?. In 15th Workshop of Applied Mechanics. Prague: CTU, Faculty of Mechanical Engineering, 2012, p. 24-25.

Kronek, J. - Chlup, H. - Žitný, R.: What affects vascular branching mechanics?. In 14th Conference on Human Biomechanics. Praha: Academy of Sciences of the Czech Republic, 2012, p. 39-41.

Kronek, J. - Růžička, P. - Chlup, H. - Horný, L. - Žitný, R.: Model of "aorta-iliac arteries" branching. In Workshop On Applied Mechanics WAM 2011. Prague: CTU, Faculty of Mechanical Engineering, 2011, p. 20-22. ISBN 978-80-01-04895-5.

Kronek, J. - Horný, L. - Chlup, H. - Gultová, E. - Hromádka, D. - et al.: Bifurcation of blood vessels as a shape and material inhomogeneity. In Human Biomechanics 2010. Liberec: Technical University of Liberec, 2010, p. 155-159. ISBN 978-80-7372-648-5.