% $$K_{t} = \frac{1-\nu_{eff}}{1-\frac{\nu_{eff}}{2}}K_{n}$$
%
% *Notation*:
%
% $\hat{t}$: Tangent direction between elements
%
% $\delta_{t}$: Tangent overlap
%
% *References*:
%
% * <https://doi.org/10.1115/1.4009973
% R.D. Mindlin.
% Compliance of elastic bodies in contact, _J. Appl. Mech._, 16(3):259-268, 1949>
% (stiffness coefficient formula)
%
classdef ContactForceT_Spring < ContactForceT
    %% Public properties
    properties (SetAccess = public, GetAccess = public)
        % Formulation options
 