Description
- Abstract:
- Ethylene-Vinyl Acetate (EVA) foam is a type of closed-cell elastomeric foam that consists of a polymeric elastomer matrix and air and is used in a wide variety of applications due to the material’s ability to dissipate energy. Midsoles in shoes, for example, greatly benefit from the properties of foam as the dissipation of energy reduces the impact on people’s feet during physical activity. Most existing constitutive models can only capture certain features of the mechanical behavior of foams during specific and limited loading conditions. As such, we focused on a recently-developed, nonlinear, large-deformation viscoelastic constitutive model for our studies due to its ability to capture mechanical responses in compression, over a wide range of strain rates, and in both loading and unloading. The first aim of this thesis focused on the material properties that appear in the constitutive model. We elucidated the role of selected material properties in the constitutive model through finite-element-based parametric studies of cyclic, uniaxial, compression-like deformation of a foam layer with a flat, circular indenter. The effects on the simulated response when varying both equilibrium and non-equilibrium material properties of the constitutive model as well as the loading frequency were studied. The second aim of this thesis was to apply the constitutive model to simulations of cyclic loading of a shoe midsole, specifically the geometry of the shoe midsole from Reebok’s Zig line of shoes. This aim utilized a three-dimensional finite-element model to simulate compression of the midsole by a flat, circular indenter. The effects on the simulated response of the midsole when varying the frequency and position of the indenter were examined. The results when varying frequency were analogous to the baseline cases of the parametric studies in the first aim, and the results when varying position were affected by the geometry of the midsole, which dictated the dominant mode of deformation in the foam.
- Notes:
- Thesis (Sc. M.)--Brown University, 2022
Citation
Roylo, Leinani Cathryn,
"Modeling of Ethylene-Vinyl Acetate (EVA) foam: Parametric studies of material properties and application to shoe midsoles"
(2022).
Mechanics of Solids Theses and Dissertations.
Brown Digital Repository. Brown University Library.
https://repository.library.brown.edu/studio/item/bdr:hjget9sz/
Relations
Collection:
-
Mechanics of Solids Theses and Dissertations
Theses and Dissertations for the Mechanics of Solids department....