A Dynamic Mechanical Analysis Technique for Porous Media
| Autor: | Adam J. Pattison, Matthew D. J. McGarry, John B. Weaver, Keith D. Paulsen |
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| Rok vydání: | 2015 |
| Předmět: |
Materials science
Viscosity Constitutive equation Poromechanics Biomedical Engineering Modulus Mechanics Dynamic mechanical analysis Physics::Classical Physics Models Biological Article Viscoelasticity Shear modulus Biopolymers Models Chemical Elastic Modulus Materials Testing Computer Simulation Geotechnical engineering Material properties Porosity Elastic modulus |
| Zdroj: | IEEE Transactions on Biomedical Engineering. 62:443-449 |
| ISSN: | 1558-2531 0018-9294 |
| DOI: | 10.1109/tbme.2014.2357771 |
| Popis: | Dynamic mechanical analysis (DMA) is a common way to measure the mechanical properties of materials as functions of frequency. Traditionally, a viscoelastic mechanical model is applied and current DMA techniques fit an analytical approximation to measured dynamic motion data by neglecting inertial forces and adding empirical correction factors to account for transverse boundary displacements. Here, a finite element (FE) approach to processing DMA data was developed to estimate poroelastic material properties. Frequency-dependent inertial forces, which are significant in soft media and often neglected in DMA, were included in the FE model. The technique applies a constitutive relation to the DMA measurements and exploits a non-linear inversion to estimate the material properties in the model that best fit the model response to the DMA data. A viscoelastic version of this approach was developed to validate the approach by comparing complex modulus estimates to the direct DMA results. Both analytical and FE poroelastic models were also developed to explore their behavior in the DMA testing environment. All of the models were applied to tofu as a representative soft poroelastic material that is a common phantom in elastography imaging studies. Five samples of three different stiffnesses were tested from 1 – 14 Hz with rough platens placed on the top and bottom surfaces of the material specimen under test to restrict transverse displacements and promote fluid-solid interaction. The viscoelastic models were identical in the static case, and nearly the same at frequency with inertial forces accounting for some of the discrepancy. The poroelastic analytical method was not sufficient when the relevant physical boundary constraints were applied, whereas the poroelastic FE approach produced high quality estimates of shear modulus and hydraulic conductivity. These results illustrated appropriate shear modulus contrast between tofu samples and yielded a consistent contrast in hydraulic conductivity as well. |
| Databáze: | OpenAIRE |
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