Cardiovascular system and artificial replacements
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 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.
Ing. Jakub Kronek Ph.D. ; doc. Ing. Lukáš Horný Ph.D. ; Hynek ChlupResesrchers:
University Hospital Na KralovskychVinohradech, Srobarova 50, 10034, Prague, Czech