# The Oka Wear Model

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 provided in terms of wear depth on geometry mesh elements similar to the Archard wear model.

The wear depth is determined as follows:

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 as follows:

where *W* is the materials wear constant, *v* is the particles impact velocity, *H**v* 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 defined as:

where captures the normalized erosion due to repeated deformation and captures the cutting behavior of the impact. Using 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 you select **Enable** **Deformation**, another input parameter called Scaling Factor is presented which allows the deformation results to be scaled as desired.

Interaction | Configuration 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 **Enable** **Deformation** in the parameter values GUI.

Material | WOka | Vickers Hardness (GPa) |

Carbon Steel | 3 | 0.54 - 1.18 |

Stainless Steel | 10 | 1.770 |

Aluminium | 1000 | 0.36 |

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