Layer-Specific Damage Modeling of Porcine Large Intestine under Biaxial Tension

The mechanical behavior of the large intestine beyond the ultimate stress has never been investigated. Stretching beyond the ultimate stress may drastically impair the tissue microstructure, which consequently weakens its healthy state functions of absorption, temporary storage, and transportation for defecation. Due to closely similar microstructure and function with humans, biaxial tensile experiments on the porcine large intestine have been performed in this study. In this paper, we report hyperelastic characterization of the large intestine based on experiments in 102 specimens. We also report the theoretical analysis of the experimental results, including an exponential damage evolution function. The fracture energies and the threshold stresses are set as damage material parameters for the longitudinal muscular, the circumferential muscular and the submucosal collagenous layers. A biaxial tensile simulation of a linear brick element has been performed to validate the applicability of the estimated material parameters. The model successfully simulates the biomechanical response of the large intestine under physiological and non-physiological loads.

Automated summary

The mechanical behavior of the large intestine beyond the ultimate stress was investigated in this study. It was found that stretching beyond the ultimate stress could impair the tissue microstructure and weaken the functions of the large intestine. The study performed experiments on porcine large intestine and validated the results through numerical simulations, obtaining the hyperelastic characterization of the large intestine.