So to the addition of my previous question, ultimately I want to combine 'Coulomb Friction' model with 3D FEM model. In that case, having a (discrete) element of such model would be a great advantage. I'm just wondering if I can develop such element in code aster or not.]]>

F = m.g.2/pi.arctan(ud/c)

where,

F = force

m= mass

g = acceleration of gravity

ud= velocity

c = reference velocity (constant)

Furthermore, the equation of motion of the total system after connecting it with SDOF system when excited by ground acceleration (uddg) becomes,

m.udd + cs. ud + ks. u + m.g.2/pi.arctan(ud/c) = -m.uddg

where,

udd = acceleration

cs = damping

ks = stiffness

u = displacement

. represents multiplication.

Any ideas, examples and suggestions are welcome. Please help..