A new framework for characterization of poroelastic materials using indentation
A new framework for characterization of poroelastic materials using indentation
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DOI：
10.1016/j.actbio.2019.11.010
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发表时间：
2020-01-15
影响因子：
9.7
通讯作者：
Moeendarbary, Emad
中科院分区：
文献类型：
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作者：
Esteki, Mohammad Hadi;Alemrajabi, Ali Akbar;Moeendarbary, Emad
为了表征多孔弹性材料，通常将压头压到材料的表面上，具有有限接近速度的斜坡，随后保持压头位移保持恒定。这导致多孔基质的变形、间隙流体的加压和由于流体通过孔的重新分布而导致的松弛。在大多数的研究中，孔隙弹性性质，包括弹性模量，泊松比和孔隙弹性扩散系数，提取假设瞬时阶跃压痕。然而，施加阶梯状压痕在实验上是不可能的，并且通常施加具有有限接近速度的斜坡压痕。此外，多孔弹性弛豫时间高度依赖于除了多孔弹性扩散系数和接触面积的接近速度。在这里，我们广泛地研究了压痕速度的影响，使用有限元模拟，使制定一个新的框架的基础上，采用了有限的上升时间的主曲线。为了验证我们的新框架，两种类型的水凝胶的多孔弹性性能提取实验使用压痕测试在宏观和微观尺度。我们的新框架是基于考虑有限的接近速度是实验上容易实现，并提供了一个更准确的估计poroelastic properties.Statement的significanceHydrogels，组织和活细胞构成的海绵状多孔弹性矩阵沐浴在间质液。已经表明，当以类似于体内器官所经历的方式进行机械刺激时，这些材料根据“多孔弹性”理论表现。在该理论中，流体填充的海绵可以变形的速率受到组织间液响应于变形在海绵内重新分布的速度的限制。在这里，我们模拟压痕实验在不同的速率，并制定了一个新的框架，固有地捕捉刺激速度对多孔弹性材料的机械响应的影响。我们通过在琼脂糖和聚丙烯酰胺水凝胶上进行不同长度尺度的实验来验证我们的框架。(C)2019 Acta Materialia Inc.爱思唯尔有限公司出版
To characterize a poroelastic material, typically an indenter is pressed onto the surface of the material with a ramp of a finite approach velocity followed by a hold where the indenter displacement is kept constant. This leads to deformation of the porous matrix, pressurization of the interstitial fluid and relaxation due to redistribution of fluid through the pores. In most studies the poroelastic properties, including elastic modulus, Poisson ratio and poroelastic diffusion coefficient, are extracted by assuming an instantaneous step indentation. However, exerting step like indentation is not experimentally possible and usually a ramp indentation with a finite approach velocity is applied. Moreover, the poroelastic relaxation time highly depends on the approach velocity in addition to the poroelastic diffusion coefficient and the contact area. Here, we extensively studied the effect of indentation velocity using finite element simulations which has enabled the formulation of a new framework based on a master curve that incorporates the finite rise time. To verify our novel framework, the poroelastic properties of two types of hydrogels were extracted experimentally using indentation tests at both macro and micro scales. Our new framework that is based on consideration of finite approach velocity is experimentally easy to implement and provides a more accurate estimation of poroelastic properties.Statement of significanceHydrogels, tissues and living cells are constituted of a sponge-like porous elastic matrix bathed in an interstitial fluid. It has been shown that these materials behave according to the theory of 'poroelasticity' when mechanically stimulated in a way similar to that experienced in organs within the body. In this theory, the rate at which the fluid-filled sponge can be deformed is limited by how fast interstitial fluid can redistribute within the sponge in response to deformation. Here, we simulated indentation experiments at different rates and formulated a new framework that inherently captures the effects of stimulation speed on the mechanical response of poroelastic materials. We validated our framework by conducting experiments at different length-scales on agarose and polyacrylamide hydrogels. (C) 2019 Acta Materialia Inc. Published by Elsevier Ltd.