Oka Wear
The Impact Wear model extends any Base Model to give an estimation of erosion depth for geometry surfaces due to particle impacts. This model originates from the work by Oka and Yoshida (Oka and Yoshida, 2005). Erosive wear occurs when particles impact equipment surfaces. This type of wear can be modeled using the widely adopted Oka wear model (Oka and Yoshida, 2004), which predicts the volume of removed material due to particle impact as a function of the particle size, impact velocity, and impact angle. Only two input parameters are required for the model – the Vicker’s hardness of the worn material and an empirical wear constant. The results in EDEM are given in terms of wear depth on geometry mesh elements similarly to the Archard wear model.
The wear depth is determined from:
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Where dw is the wear depth, α is the particle impact angle, g(α) is the impact angle dependence of normalized erosion, E(α) is the wear volume per unit mass, mp is the mass of the particle and A is the geometry element area:
The wear volume per unit mass is derived from:
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Where W is the materials wear constant, v is the particles impact velocity, Hv is the Vicker’s hardness of worn material, D is the particle diameter and k1 is an experimentally derived coefficient.
The impact angle dependence of normalized erosion is given by:
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Where .svg){kind=small}
captures the normalized erosion due to repeated deformation and .svg){kind=small}
captures the cutting behaviour of the impact.
To use this model in EDEM requires the additional input of the material’s Vickers hardness, Hv (GPa), the material’s Wear Constant, WOka. EDEM also offers the option to deform the geometry according to the quantitative results given by the impact wear model. If the Enable Deformation option is selected another input parameter, Scaling Factor, is presented which allows the deformation results to be scaled as desired.
| Interaction | Configurable Parameters | Position |
| Particle to Geometry | Assign a Wear Constant, Vickers Hardness value for each Equipment Material-Particle interaction and Scaling Factor (if Deformation enabled). | Last |
To enable geometry deformation select the “Enable Deformation” option in the parameter values GUI shown below. Please note that geometry deformation is currently only available on the CPU.
|
Material |
WOka |
Vickers Hardness (GPa) |
|
Carbon Steel |
3 |
0.54 - 1.18 |
|
Stainless Steel |
10 |
1.77 |
|
Aluminium |
1000 |
0.36 |