When two or more solids interact, they impact each other in a multitude of ways. In an assembly that includes multiple components, the interaction between those components can become quite complex. Before those assemblies can be put together physically, the components’ interactions must be modeled virtually in order to predict the effects they will have on each other and on the entire assembly. This is known as contact modeling.

Contact modeling has come a long way in a relatively short period of time. Not long ago, contact modeling software offered the opportunity to virtually combine components in multiple pairings, but as of more recently users have been able to model all possible interactions for assemblies. Abaqus is the leader in contact modeling, and as contact modeling has advanced in general, it has also advanced in Abaqus/Standard and Abaqus/Explicit.

In Abaqus/Standard, the primary formulation is surface-to-surface contact. Supplementary formulations include edge-to-edge, edge-to-surface and vertex-to-surface. As contact modeling has evolved, the transitions between active formulations have become automatic.

Recent contact modeling developments in Abaqus include:

• A new small-sliding formulation. Small-sliding uses a planar representation of the master surface per slave mode based on the initial configuration. In Abaqus/Explicit, users now have the option to gradually resolve initial overclosure across increments in the first step.
• Less memory is needed for interior surfaces, which are regions that do not have currently exposed faces.
• CEL contact has been improved – the CEL contact formulation works well not only for solids, but for modeling liquids and gases as well. The existing formulation can exhibit leakage, but a new contact formulation that avoids leakage is under development.
• Bolt thread modeling has also been improved. Contact normal is associated with the top or bottom of the thread face, and both right-handed and left-handed threads can be modeled. Users can efficiently capture approximate stresses due to thread contact without modeling detailed thread geometry, which enables the prediction of fatigue life and the probability of loosening.
• General contact in Explicit now supports axisymmetric and 2D models, which were already supported by general contact in Standard. Simple, fast contact definition increases user efficiency while parallel scaling enables fast turnaround times and more robust designs.
• In Abaqus/Standard, general contact now supports pure heat transfer and coupled thermal/electrical procedures. Identical contact definitions can be used across sequential thermal-stress analysis.

SIMULIA R&D is continuously expanding the scope of general contact in Abaqus, so that users can more efficiently model contact within even the most complex assemblies. To learn more about contact overall as well as new features Abaqus has to offer, check out the webinar “Contact Robustness and Performance,” which can be accessed here.