Dataset for: A finite element approach for gastrointestinal tissue mechanics

The biomechanical properties of gastrointestinal (GI) tissue play a significant role in the normal functioning of the organ. GI soft tissues exhibit a highly nonlinear rate- and time-dependent stress-strain behaviour. In recent years, many constitutive relations have been proposed to characterise these properties. However, a constitutive relation is not sufficient to analyse the biomechanics at the organ level with complex loading and boundary conditions. Hence, for a refined mechanical analysis, a finite element (FE) implementation of the constitutive relation is needed. Here, we propose a FE implementation of a finite nonlinear hyper-viscoelastic model suitable for soft biological tissues. The FE model has been validated at first by comparing its results with the analytical solutions of a standard linear solid, and then it has been used to recreate experimental observations performed on tissue strips obtained from different animals. We have also proposed a method, in this work, to construct a residually stressed FE model so that the consequences of residual stresses on GI mechanics can be examined. Our FE formulation was able to capture the nonlinear soft tissue properties and also demonstrated that the addition of residual stresses reduces stress concentrations as well as the stress gradient in the GI wall.

胃肠道（gastrointestinal, GI）组织的生物力学特性对该器官的正常功能具有重要作用。胃肠道软组织表现出高度非线性的、与速率和时间相关的应力-应变行为。近年来，已有诸多本构关系被提出以表征此类特性。然而，仅依靠本构关系不足以分析存在复杂载荷与边界条件的器官级生物力学问题。因此，为开展精细化的力学分析，需将本构关系进行有限元（finite element, FE）实现。本文提出了一种适用于生物软组织的有限非线性超粘弹性模型的有限元实现方案。该有限元模型首先通过与标准线性固体的解析解对比完成验证，随后被用于复现从不同动物获取的组织条带的实验观测结果。本研究同时提出了一种构建带残余应力的有限元模型的方法，以考察残余应力对胃肠道力学行为的影响。我们的有限元公式不仅能够准确捕捉软组织的非线性力学特性，还证实了引入残余应力可降低胃肠道管壁的应力集中与应力梯度。