This post is still under construction and will be added to over the next few days.
M.T. Petre , A. Erdemir & P.R. Cavanagh (2006) Determination of elastomeric foam parameters for simulations of complex loading, Computer Methods in Biomechanics and Biomedical Engineering, 9:4, 231-242, DOI: 10.1080/10255840600747620
This paper is very interesting in part because the authors also shared publicly a large quantity of resilient foam test data. The test data is for a large set of foams, and includes uniaxial compression, simple shear and volumetric compression testing. The paper also makes the point that just testing a foam in uniaxial compression, then calibrating, may create a material model that behaves very incorrectly in shear. It is also uncommon to see volumetric testing performed on a foam, which the authors do by way of a very interesting test apparatus (see video).
The full set of test data (for many foams) is shared in this post: Poron Foam ; Petre_Erdemir_2006
EVA stands for Ethylene-vinyl acetate.
The Cyclic Uniaxial Compression data shown in the image above has a
And a stress response like this:
Looking at the 1st image (stress vs strain), I would conclude there is a bit of a Mullins effect in this material. For end applications that focus on repeat loading, one might want to ignore the Mullins effect. EVA foams are often used in running shoes where the initial Mullins effect is not so important to capture.
Looking closely at the strain/stress waveforms and the video below, I conclude that faithfully representing the cyclic compressive test requires a FE model with contact. The video is just a sample of the test, not the EVA foam.
If one uses the Numerical mode in the 3DExperience Material Calibration App, the stress response during unloading (green ellipse) cannot follow the test response.
When one uses an FE model (unit-cube) with a rigid contact surface, during the unload the contact surface loses contact with the deformable body, which faithfully represents the test conditions.
This is an image from the Calibration App, using Numerical mode. The cyclic compressive test is truncated at the end of the unload
The attached test data file was downloaded from the
https://simtk.org/projects/elastomericfoam
And is posted here under the terms of the Creative Commons use agreement. No changes have been made to this data.
This work by Marc Thomas Petre is licensed under a Creative Commons Attribution 4.0 International License, see http://creativecommons.org/licenses/by/4.0/
Please cite:
Petre, M., Erdemir, A. and Cavanagh, P. R. (2006) Determination of elastomeric foam parameters for simulations of complex loading, Computer Methods in Biomechanics and Biomedical Engineering, 9, 231-242.
Petre, M. T. Determining material parameters for multi-axial simulations of elastomeric foams, MSc Thesis, Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA, 2005.
SimTK: Determination of elastomeric foam parameters for simulations of complex loading: Project Home. Available at: https://simtk.org/projects/elastomericfoam.
Downloads
The download includes mechanical testing data on elastomeric foams; shear, unconfined compression and volumetric compression, collected during the course of Marc Thomas Petre's master's thesis. This work by Marc Thomas Petre is licensed under a Creative Commons Attribution 4.0 International License, see http://creativecommons.org/licenses/by/4.0/. Please cite: Petre, M., Erdemir, A. and Cavanagh, P. R. (2006) Determination of elastomeric foam parameters for simulations of complex loading, Computer Methods in Biomechanics and Biomedical Engineering, 9, 231-242.
