Elasto Gap $—$ 1D translational spring-damper combination with gap

A linear parallel spring-damper combination that can lose contact with flange_a; thus, the spring-damper can only push. Pushing is identified as:

1) The spring is compressed.

AND

2) The damper extension force is less than spring compression force.

 Equations $\left\{\begin{array}{cc}-f=\mathrm{min}\left(0,\mathrm{f_c}+\mathrm{f_d}\right)& \mathrm{f_c}<0\\ f=0& \mathrm{otherwise}\end{array}\right\$ $\mathrm{f_c}=c\left({s}_{\mathrm{rel}}-{s}_{\mathrm{rel0}}\right)$ $\mathrm{f_d}=d{v}_{\mathrm{rel}}$ ${s}_{\mathrm{rel}}=\mathrm{switch}\left(\mathrm{flange_b.s}-\mathrm{flange_a.s}\right)$ ${v}_{\mathrm{rel}}={\partial }_{t}\left({s}_{\mathrm{rel}}\right)$ $\mathrm{flange_a.f}\mathrm{switch}=f$ $\mathrm{flange_a.f}+\mathrm{flange_b.f}=0$

Variables

 Name Value Units Description Modelica ID ${s}_{\mathrm{rel}}$ $m$ Relative position s_rel $f$ $N$ Force between flanges f

Connections

 Name Description Modelica ID ${\mathrm{flange}}_{a}$ flange_a ${\mathrm{flange}}_{b}$ flange_b

Parameters

 Name Default Units Description Modelica ID $\mathrm{reverse}$ $\mathrm{false}$ Reverse the sign convention, see documentation for details reverse ${s}_{\mathrm{rel0}}$ $0$ $m$ Preload distance s_rel0 $c$ $1$ $\frac{N}{m}$ Spring rate c $d$ $1$ $\frac{Ns}{m}$ Damping rate d