The mechanical properties of the aortic wall are important to develop a biofidelic finite element model. In this study, the influence of the location on the deformation characteristics along the descending aorta was investigated on 53 samples of pig aortic specimens. Uniaxial tensile tests up to failure were carried out at a strain rate of 68 s−1 in the longitudinal direction. Cauchy stress‐true strain relationships were determined and compared for 4 different locations from the aortic arch to the abdominal aorta. Digital Image Correlation (DIC) was used to determine the Green‐Lagrange full field strain. The experiments showed that the Cauchy stress vs. true strain relationship is more representative of the large deformation of the tissue than the engineering stress‐strain curves. The influence of the location was not found to be significant for engineering stress (mean value 1.2±0.3 MPa) whereas a significant difference (p<0.005) between the aortic arch (3.4 MPa) and the thoracic aorta (2.7 MPa) was found for the Cauchy stress. The Green Lagrange strain at rupture measured for the aortic arch was found to be significantly higher (4.0) compared to the one measured for the thoracic aorta (1.9). The present study demonstrates the utility of the DIC to determine the local strain fields and to analyze the tissue failure mechanisms. Different rupture patterns were observed.
Keywords:
Aorta, full strain field, structural characteristics, failure pattern, Digital Image Correlation