Product: ABAQUS/Standard
Benefits: There is a strong interest in modeling a tire with a full tread pattern to gain a better understanding of the interaction of a moving tire with the road. Calculations can then be made locally of the wear on the tread and globally of the state of the rolling tire: full braking, free rolling, or full traction. The existing tire analysis capabilities in ABAQUS have been extended to facilitate steady-state transport simulations of a tire with accurate tread geometry.
Description: It is computationally expensive to model rolling contact, such as a tire traveling along a road using a traditional Lagrangian formulation since the frame of reference in which motion is described is attached to the material. The steady-state transport analysis method in ABAQUS/Standard uses a mixed Eulerian/Lagrangian approach in which the rigid body rotation is described in an Eulerian manner and the deformation is described in a Lagrangian manner. This kinematic description converts the steady-state moving contact problem into a purely spatially dependent simulation.
The steady-state rolling capability in ABAQUS/Standard provides solutions that include frictional effects, inertia effects, history-dependent material, rate-independent material, and rate-dependent material effects for a model with axisymmetric geometry. ABAQUS/Standard also provides features for simulating the response of periodic geometries, such as a vented disc brake. However, in this case no convective effects are considered between the contact surfaces, and the frictional stress does not depend on any history effects. These assumptions are appropriate for a disc brake analysis where deformations remain small.
In a rolling tire analysis where deformation near the footprint is significant, the local material velocity depends on the streamline deformation and the convective effects must be considered when evaluating the frictional stress. The steady-state transport procedure has now been enhanced to account for such effects in a periodic geometry.
Enhancements have also been made to the symmetric model generation capability to allow each sector in a generated model to have a variable angle in the circumferential direction so that the pitch sequence can be defined correctly for a tread tire geometry. Each sector, however, will have the same geometry and mesh. The symmetric results transfer capability is also supported for a periodic geometry with a variable angle for each sector. Figure 6–5 and Figure 6–6 show examples of the enhancements to the symmetric model generation capability.
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