Self contact during deformation using Partitions

Hi Tim,

Great question — you're tackling a common challenge in flexible body simulations where self-contact is needed, but the structure must still behave as a single deformable continuum. Using partitions is a smart approach, but using locked joints between them introduces artificial constraints that over-restrict deformation, which explains the discontinuities you're seeing in the deformation plots.

the core issue:

Locked joints rigidly bond the partitions together — so they don't deform like a continuous material. This breaks the physics of large deformation where strain should be smooth across the entire tire structure. In reality, all tire regions remain deformably connected, even if in contact with themselves.

Avoid:

• Avoid using rigid body joints (locked, pinned, etc.) for flexible deformation modeling.
• Avoid splitting the tire into separate parts unless you explicitly want them to behave independently (which is not the case here).

To simulate self-contact in a deformable tire while maintaining realistic, continuous deformation, the best approach is to use partitions without connecting them through rigid joints like locked joints. Although partitions allow you to define separate contact regions, using joints between them introduces artificial constraints that prevent the tire from deforming naturally, resulting in discontinuities in the deformation plot. Instead, the partitions should remain part of a single, continuous solid body so that the mesh connectivity ensures physical continuity across the structure. You can then define motion contact sets between the partitioned surfaces to simulate self-contact behavior during deformation. These contact definitions allow the solver to treat each partition surface as a separate contact region, even though they are part of the same physical body. It’s important not to split the partitions into separate parts, as this would break the deformable behavior of the tire. Additionally, ensure the mesh remains continuous across partitions to accurately capture large strain effects. If Inspire's capabilities are limited for this kind of self-contact, exporting the model to MotionSolve or Radioss can offer more advanced contact handling features. Overall, the key is to rely on mesh and material continuity, not rigid constraints, to preserve the flexible behavior while enabling internal contact detection.

FYI: To allow self-contact in a deformable tire model while maintaining realistic and continuous deformation, the tire surface should be logically partitioned but kept as a single part rather than split into separate solids. This ensures that the mesh remains continuous, preserving the natural strain behavior of the material. Motion contact definitions should be applied between the partitioned surfaces to simulate self-contact effectively during deformation. It is important to avoid using joints, such as locked joints, between partitions, as they introduce artificial stiffness and constraints that disrupt the natural deformation of the model. By maintaining a unified, meshed structure and using appropriate contact settings, the simulation will reflect accurate and physically realistic self-contact behavior.

Regards,

Sourav