The effect of stress and strain formulations on the representation of biological tissue mechanical properties - biomed 2009.
With the increasing use of computational models there is a growing need to establish and analyze the material properties of biological tissues. The purpose of this study is to analyze and compare the various methods used for reporting stress and strain for biological materials. For this study, three biological materials (bone, sclera, and placenta) were used to compare the effects of reporting stress and strain relationships using various formulations. For each material the engineering, 2nd Piola Kirchhoff and true stresses were calculated along with the engineering, Green-Lagrangian, and true strains. The energetic equivalents were then plotted to investigate the various formulations. As expected, it was found that for strain values less than 5% the various formulations were not significantly different but as the strain increased (30%) the non-linear terms began to increase the difference between the formulations to a maximum of 36%. Also, to represent a material correctly, the energy conjugates must be used together. Measuring the true stress and true strain relationship is advantageous given that most computational models use this formulation.
Virginia Tech-Wake Forest Center for Injury Biomechanics, Blackburg, VA.
Jill A
JA
Bisplinghoff
Stefan M
SM
Duma