A Unified Contact Detection Approach for Modeling Non-Smooth Contact

"Computational contact modeling techniques are highly relevant and challenging in most engineering applications. When two independent bodies interact under load in a finite element model, surface-to-surface contact elements are used by the more sophisticated FEA codes to manage the interaction. The gap or penetration between the contact and the target element is calculated with respect to the detection methods. There is no optimal detection method that works best for all contact conditions, so a few codes offer several options for contact detection about a contact detection point or on a projected area from the contact element face onto the target surface. However, in some cases one detection method is obviously good for the earlier stage of the deformation configuration but other detection methods will be suitable for the later stage of deformation configuration.

The aim of this contribution is to develop a unified contact detection method which combines different contact detection methods together. In conjunction with using symmetric contact definition, the technique adds more contact constraint points at contact interface and results in much less penetration and less mesh sizing sensitivity. In addition, both linear order and quadratic order underlying elements are supported. 10 node quadratic tetrahedron is the most common used element in today’s finite element models since the generation of elements can be done fully automatically. Therefore, the whole modeling process is fully automatic without too much user intervention. It robustly solves non-smooth contact conditions with mixed surface-to-surface, edge-to-surface and corner-to-surface scenarios undergoing large deformations. Challenging contact applications (such as interference fit, press fit, snap fit, and snap through) were difficult to solved in the past but now are easily solved by the present approach.

Almost all Ansys Mechanical users rely on nonlinear contacts to successfully simulate and design their parts. Recent performance of Ansys Mechanical solver against other competitive codes in several large cooperations has shown that the new method outperforms codes like Abaqus or Optistruct when resolving the most challenging contact models."