ing collisions.</p><p><img src="ContactForceN_ElastoPlasticLinear_eq00707627108190457159.png" alt="$$\left \{ F_{n} \right \} = -F_{n}^{e} \{-\hat{n}\}$$" style="width:112px;height:15px;"></p><div><ul><li><b>Loading</b> (<img src="ContactForceN_ElastoPlasticLinear_eq07199587971001351588.png" alt="$\dot{\delta_{n}}&gt;0$" style="width:39px;height:17px;">):</li></ul></div><p><img src="ContactForceN_ElastoPlasticLinear_eq12773691268591185211.png" alt="$$F_{n}^{e} = K_{n}^{L}\delta_{n}$$" style="width:70px;heig