  Helical torsion springs with tangential legs are used for many applications:
from simple everyday use systems, like clothes peg, to advanced systems, as
sectional doors. Torsion springs are usually exploited with an inner rod as a
guide. The required space between the spring and the rod make the spring
tilted. Unfortunately, as far as we are aware, no industrial software is able
to determine the initial system angle made by the spring in its tilted
position. All the torque/angle curves are presented with relative angles. It
means that whatever the number of coils considered, the angle is null when the
torque is null. For that reason, we have developed a methodology using both
CATIA and ABAQUS to determine the system angle at the beginning of the
behavior. The model exploits wires designed with CATIA and imported in ABAQUS
for the center rod, the torsion spring and the rods of the system to apply the
torque. Several options to model contact between the several parts have been
investigated. They mostly use connector with an axial property and a stop
criterion. The obtained results are very interesting and enable to plan further
studies.
