Surface and interfacial creases in a bilayer tubular soft tissue

Abstract

Surface and interfacial creases induced by biological growth are common types of instability in soft biological tissues. This study focuses on the criteria for the onset of surface and interfacial creases as well as its morphological evolution in a growing bilayer soft tube within a confined environment. Critical growth ratios for triggering surface and interfacial creases are investigated both analytically and numerically. Analytical interpretations provide preliminary insights into critical stretches and growth ratios for the onset of instability and formation of both surface and interfacial creases. However, the analytical approach cannot predict the evolution pattern of the model after instability, therefore non-linear finite element simulations are carried out to replicate the post-stability morphological patterns of the structure. Analytical and computational simulation results demonstrate that the initial geometry, growth ratio, and shear modulus ratio of the layers are the most influential factors to control surface and interfacial crease formation in this soft tubular bilayer. The competition between the stretch ratios in the free and interfacial surfaces is one of the key driving factors to determine the location of the first crease initiation. These findings may provide some fundamental understanding in the growth modeling of tubular biological tissues such as esophagi and airways as well as offering useful clues into normal and pathological functions of these tissues.

Mechanism of Consistent Gyrus Formation: an Experimental and Computational Study

“…There are several proposed material behaviors for hyperelastic materials. Here a simple and common model with a nonlinear neo-Hookean behavior is implemented323457585960.…”

Peristaltic Elastic Instability in an Inflated Cylindrical Channel

“…This introduces a range of geometrically motivated elastic instabilities into their mechanics, including buckling [9], creasing [10][11][12][13][14][15] and wrinkling [16,17] under compression; fingering [18][19][20][21][22], fringing [23,24] and beading [25][26][27][28] under tension; and ballooning [29][30][31][32][33], aneurysm [30,34] and cavitation [35][36][37] under inflation. These instabilities are important failure modes of soft/biological systems [38], but have also been exploited by evolution to sculpt developing brains [39,40], guts [41,42] and other organs [43][44][45][46][47], and by engineers to make shape-switching devices [48][49][50][51]. The inflated channel instability we report here is a further example, with an analogous relationship to aneurysm as the sulcus instability has to buckling.…”

Mechanical properties of the airway tree: heterogeneous and anisotropic pseudoelastic and viscoelastic tissue responses

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