tyle="width:16px;height:13px;"> can be computed as a function of the normal stiffness coefficient <img src="ContactForceT_Spring_eq01324158102978469580.png" alt="$K_{n}$" style="width:18px;height:13px;"> and the effective Poisson ratio <img src="ContactForceT_Spring_eq12508299283340161401.png" alt="$\nu_{eff}$" style="width:24px;height:11px;">:</p><p><img src="ContactForceT_Spring_eq00322000344675749432.png" alt="$$K_{t} = \frac{1-\nu_{eff}}{1-\frac{\nu_{eff}}{2}}K_{n}$$" style="width:109px;height:35px;"></