On modelling damage process in vaginal tissue.
ABSTRACT The goal of this study was to characterize and model the damage process in prolapsed vaginal tissue undergoing finite deformations. Experiments in prolapsed vaginal tissue revealed that a softening process occurs before tissue's rupture. This nonlinear damage behavior requires a continuum damage theory commonly used to describe the softening behavior of soft tissues under large deformations. The structural model here presented was built within the framework of nonlinear continuum mechanics. Tissue damage was simulated considering different damage behaviors for the matrix and the fibers. The model parameters were fit to the experimental data obtained from prolapsed vaginal tissue undergoing finite deformations in uniaxial tension tests. The tests were developed with samples cut along the longitudinal axis of the vagina. The damage model was able to predict the stress-strain behavior and the damage process accurately. The error estimations pointed to an excellent agreement between experimental results and model fittings. For all the fitted data, the normalized RMS error epsilon presented very low values and the coefficient of determination R2 was close to 1.