Undergraduate/Graduate Category: Graduate Degree Level: Master ...
Undergraduate/Graduate Category: Graduate Degree Level: Master Abstract ID# 1210 Abstract Cartilage is a poroelastic tissue with nearly 80% water content. Mechanics of poroelastic materials are dependent on the flow properties of the fluid (permeability) and the material properties of the solid (G, shear modulus). This project is to calculate the permeability of cartilage from indentation experiments, and validate the results with poroelastic finite element models. This project computes permeabilities through fitting experimental force versus time curve to the analytical curve we have known. In addition, this project also models a cartilage and the loading process in ABAQUS. By comparing the results from ABAQUS with those from fitting, we can test and verify if our code or modeling is correct. This method is able to be used as a general solution to calculate the permeabilities based on the data from indentation. Introduction Indentation has been used to characterize material’s properties for a long time. When an indenter is pressed into the cartilage to a fixed depth, the solvent in it migrates, and the force on the indenter relaxes.
Method In our project, a spherical indenter was used to implement indentation. For a spherical indenter: Based on the formulas we have , where
And
,
, D can be solved. ,
, and
are shear modulus,
permeability, poison’s ratio and viscosity, respectively. Where
/
We extracted the force and time from experimental data and fit them to the analytical curve we have known (
) , through nonlinear least‐squares method to fit curve using MATLAB.
Also, we simulate the indentation using ABAQUS, the model is shown as follows: We used CAX8P element type and contact model to simulate the indentation. Higher density of mesh elements is used on contact surface.
Results For a nano‐indentation experiment (the radius of indenter is 175 µm and the depth is 2.996 nm), we calculated the permeability based on the time‐force data, and plot the curve for experimental data and fitting data.
In this project, we calculated the permeability based on the data (time and force) of indentation experiment. In the meantime, I simulate the indentation with poroelastic finite elment model using ABAQUS, and compared the results of the permeability I used in ABAQUS with the one calculated using MATLAB code Conclusion
1.2091
10
/
Goodness of fit: 0.9188
To validate our code, we calculated the permeability by using the data from finite element simulation using ABAQUS. The k ( 1.2091 10 / )we got using MATLAB code is close to the one we used in ABAQUS (2 10 / ).
Acknowledgements
Reference
In this project, we successfully generated a general solution for I would like to express my gratitude to Professor Shfelbine. Yuhang Hu, Xuanhe Zhao et al: Using indentation to calculation of permeabilities based on the results from indentation. Also, Without her instruction and encouragement, this project characterize the poroelasticity of gels. Journal of Applied we validate the data using finite element model. However, all the could not be completed. Physics Letters 96, 121904 (2010) calculation and simulation were done on the assumption that it is a spherical indenter and the range of permeability we tested is limited.
Method In our project, a spherical indenter was used to implement indentation. For a spherical indenter: Based on the formulas we have , where
And
,
, D can be solved. ,
, and
are shear modulus,
permeability, poison’s ratio and viscosity, respectively. Where
/
We extracted the force and time from experimental data and fit them to the analytical curve we have known (
) , through nonlinear least‐squares method to fit curve using MATLAB.
Also, we simulate the indentation using ABAQUS, the model is shown as follows: We used CAX8P element type and contact model to simulate the indentation. Higher density of mesh elements is used on contact surface.
Results For a nano‐indentation experiment (the radius of indenter is 175 µm and the depth is 2.996 nm), we calculated the permeability based on the time‐force data, and plot the curve for experimental data and fitting data.
In this project, we calculated the permeability based on the data (time and force) of indentation experiment. In the meantime, I simulate the indentation with poroelastic finite elment model using ABAQUS, and compared the results of the permeability I used in ABAQUS with the one calculated using MATLAB code Conclusion
1.2091
10
/
Goodness of fit: 0.9188
To validate our code, we calculated the permeability by using the data from finite element simulation using ABAQUS. The k ( 1.2091 10 / )we got using MATLAB code is close to the one we used in ABAQUS (2 10 / ).
Acknowledgements
Reference
In this project, we successfully generated a general solution for I would like to express my gratitude to Professor Shfelbine. Yuhang Hu, Xuanhe Zhao et al: Using indentation to calculation of permeabilities based on the results from indentation. Also, Without her instruction and encouragement, this project characterize the poroelasticity of gels. Journal of Applied we validate the data using finite element model. However, all the could not be completed. Physics Letters 96, 121904 (2010) calculation and simulation were done on the assumption that it is a spherical indenter and the range of permeability we tested is limited.
