A continuum mechanics-based musculo-mechanical model for esophageal transport

Abstract

In this work, we extend our previous esophageal transport model using an immersed boundary (IB) method with discrete fiber-based structures, to one using a continuum mechanics-based model that is approximated based on finite elements (IB-FE). To deal with the leakage of flow when the Lagrangian mesh becomes coarser than the fluid mesh, we employ adaptive interaction quadrature points for Lagrangian-Eulerian interaction equations based on a previous work. In particular, we introduce a new anisotropic adaptive interaction quadrature rule. The new rule permits us to vary the interaction quadrature points not only at each time-step and element but also at different orientations per element. For the material model, we extend our previous fiber-based model to a continuum-based model. We first study a case in which a three-dimensional short tube is dilated. Results match very well with those from the implicit FE method. We remark that in our IB-FE case, the three-dimensional tube undergoes a very large deformation and the Lagrangian mesh-size becomes about 6 times of Eulerian mesh-size. To validate the method in handling fiber-matrix material models, we perform a second study on dilating a long fiber-reinforced tube. Errors are small when we compare numerical solutions with analytical solutions. The technique is then applied to the problem of esophageal transport. We present three cases that differ in the material model and muscle fiber architecture. The overall transport features are consistent with those from the previous model. We remark that the continuum-based model can handle more realistic and complicated material behavior. This is demonstrated in our third case with spatially varying fiber architecture. We find this unique muscle fiber architecture could generate a so-called pressure transition zone. This suggests an important role of muscle fiber architecture in esophageal transport.

47 pages, 17 figures

References in corpus (2)

• Immersed boundary model of aortic heart valve dynamics with physiological driving and loading conditions
• A fully resolved active musculo-mechanical model for esophageal transport

Cited by in corpus (7)

• An Immersed Interface Method for Discrete Surfaces
• On the Lagrangian-Eulerian Coupling in the Immersed Finite Element/Difference Method
• Esophageal virtual disease landscape using mechanics-informed machine learning
• Mechanics Informed Fluoroscopy of Esophageal Transport
• An immersed peridynamics model of fluid-structure interaction accounting for material damage and failure
• Pumping Patterns and Work Done during Peristalsis in Finite-length Elastic Tubes
• MRI-MECH: Mechanics-informed MRI to estimate esophageal health