3741913129.png" alt="$\dot{\delta}_{n}^{0}$" style="width:13px;height:18px;">: Time rate of change of normal overlap at the impact moment</p><p><img src="ContactForceN_ElastoPlasticLinear_eq02602891172830952942.png" alt="$R_{eff}$" style="width:28px;height:15px;">: Effective contact radius</p><p><img src="ContactForceN_ElastoPlasticLinear_eq02651269392019945628.png" alt="$E_{eff}$" style="width:28px;height:15px;">: Effective Young modulus</p><p><img src="ContactForceN_ElastoPlasticLinear_eq06291617511541824