Internal combustion engines produce a fluctuating torque due to discrete
combustion events, as well as inertial actions of the reciprocating masses. In
standard operating conditions, the resulting torsional oscillations of the
crankshaft are transferred to the gearbox, leading to a number of comfort
problems. Dual mass flywheels (DMF) may be a solution to reduce torsional
oscillations. They consist of a primary mass connected to the engine, a
secondary mass connected to the transmission shaft and two or more sets of arc
springs placed between the two rotary inertias. Friction between the primary
mass and the arc springs ensure an additional source of damping when the arc
springs are not loaded. This paper presents a discussion of the 3D nonlinear
dynamic effects introduced in the driveline by an automotive DMF. A model
for the DMF is developed and included into a multi-body model of the
vehicle powertrain to assess the effect of its main parameters on the
driveline behaviour (e.g. modes of vibration, radial forces). The DMF is
modelled by primary and secondary masses and the arc springs between them.
Centrifugal effects and redirection forces acting on the springs as well as
nonlinear contact forces due to stoppers and flanges bounding spring
motion are accounted for. Moreover, friction occurring in seals and friction
resulting from the spring radial forces are included. Contact forces between
primary and secondary masses of DMF with arc springs are modelled
with a penalty approach and a contact detection algorithm. The developed
3D MB model has been compared with experimental data to assess its
capability to reproduce DMF dynamics. A good correlation was found between
numerical and experimental data during torsion tests at standstill and
small displacement cycles at different angular speeds. Complex frictional
phenomena like arc spring stiffening and hysteresis cycle shrinking with
increasing angular speed are correctly captured, furthermore radial forces
exchanged between DMF stages and transmission shafts can be evaluated
thanks to a full 3D model
