/ e2;
                case this.VARIABLE
                    fmax = this.stiff * v0 * sqrt(m/this.stiff);
                    this.unload_stiff = this.stiff + S * fmax;
            end
            
            % Residual overlap
            this.residue = v0 * sqrt(m/this.stiff) * (1-e2);
        end
        
        %REPLACE_WITH_DASH_DASHREPLACE_WITH_DASH_DASHREPLACE_WITH_DASH_DASHREPLACE_WITH_DASH_DASHREPLACE_WITH_DASH_DASHREPLACE_WITH_DASH_DASHREPLACE_WITH_DASH_DASHREPLACE_WITH_DASH_DASHREPLACE_WITH_DAS