Contact Enhancements

Since 2018 release, contact algorithm has seen many valuable functionality enhancements both for standard and explicit. This year has somewhat similar stories as well. So here we go:

• Feature Edge Enhancements: This feature has been introduced in earlier release for explicit. The prior default was to consider only perimeter and beam edges for active contacts that was modified to consider additional edges for contact as they evolve during simulation. Beginning 2022 GA, this is the default criteria in explicit.

*Surface Property Assignment, Property=Feature Edge Criteria

• Dynamic Allocation: Imagine a large general contact domain only a small subset of which contributes towards contact. A large static allocation of internal elements and nodes results in performance drag. Beginning 2022GA standard, dynamic allocation scheme has been introduced that results in 10% to 20% performance improvement. A great feature of general contact of large models.

• Exclusions in General Contact: Usually contact pair approach easily allows to deactivate contact pairs with change in step, if required. This is the conventional model change approach in input deck language which can be achieved through interactions manager in Abaqus CAE. Beginning 2022GA, the similar functionality has been introduced for general contact in standard though the keywords are different.

Beam contact Enhancement: In case of beams with non circular cross sections, Abaqus used to approximate the cross section with that of a circumscribed circle. That resulted in unrealistic gaps at the contact location. The images below pictorially shows what happened behind the scenes. Beginning 2022xFD01, this beam to beam contact algorithm has been modified in explicit to capture the actual cross section shape.

*Contact Controls Assignment, Beam Cross Section = Circumscribed Circle(default)/EXACT

• Fluid Pressure Penetration: DSLOAD of type PPEN has been introduced in explicit to pressure penetration surface loading. This loading is different from conventional pressure loading as it can identify the wetted surface based on applied pressure load and contact pressure between parts. The simulation results based on this type of loading can tell whether fluid will penetrate from one cavity to the other or not. Introduced in 2022xFD02.

Fluid Pressure Penetration: DSLOAD of type PPEN has been introduced in explicit to pressure penetration surface loading. This loading is different from conventional pressure loading as it can identify the wetted surface based on applied pressure load and contact pressure between parts. The simulation results based on this type of loading can tell whether fluid will penetrate from one cavity to the other or not. Introduced in 2022xFD02.

Constraint Enhancements

• C3D10 Constraint: This element type is known to show noise in stress output in regions of contact and constraint. That’s why its modified form C3D10M was introduced in previous release. Now this element type itself has been fixed to reduce noise when used with tie constraints or couplings. Now its not mandatory to use expensive C3D10M for noise reduction.

Diagnostics Enhancement: We are aware of drag in performance when boundary conditions are applied on nodes that also participate in tie constraints or couplings. In standard, the performance drag appears in form of convergence. In explicit, it appears in form of additional system of equations that are usually not printed out as warning messages. Beginning 2022xFD01, messages about additional system of equations due to such over constraints will be printed out in explicit.