Negative Poisson ratios and strain-dependent mechanical properties in arterial prostheses.
The elastic properties of two artificial arterial prostheses have been measured. One is a fibrillar polyurethane (PU) material, the other is an expanded polytetrafluoroethylene (ex-PTFE). It is shown that the conventional assumption of incompressibility is invalid for both materials and that changes in the thickness of the prosthetic artery wall must be measured directly. The ex-PTFE shows highly strain-dependent properties, the most significant being that of large negative through-thickness Poisson ratios, up to -11. These results have important consequences for matching the properties of prostheses to natural materials.
Caddock
B D
BD
Department of Materials Science and Engineering, University of Liverpool, UK.
Evans
K E
KE
D016880:Anisotropy; D001158:Arteries; D001807:Blood Vessel Prosthesis; D004548:Elasticity; D008855:Microscopy, Electron, Scanning; D016012:Poisson Distribution; D011138:Polytetrafluoroethylene / Q000737:chemistry*; D011140:Polyurethanes / Q000737:chemistry*; D013314:Stress, Mechanical; D013718:Tensile Strength
D011140:Polyurethanes; D011138:Polytetrafluoroethylene