Description: A true surface-to-surface approach has been added for the generation of mesh tie constraints. In contrast to the existing node-to-surface approach, this new approach does not lead to stress oscillations at the interface in the case of mismatched meshes. This is particularly significant for meshes with second-order elements and most strongly for meshes with second-order tetrahedral elements. You can select the new surface-to-surface approach or the existing node-to-surface approach for any tie constraint. The surface-to-surface approach is the default in ABAQUS/Standard, whereas the node-to-surface approach is the default in ABAQUS/Explicit. In some cases the surface-to-surface approach can result in significantly increased computational costs; if local stress accuracy is not an important consideration, use of the node-to-surface approach may be preferred. For example, this may be the case for shell meshes with a large number of tied constraints. If the slave surface mesh is much coarser than the master surface mesh, the computational cost can be reduced significantly by reversing the slave and master surfaces in the contact pair definition. This will usually improve the accuracy of the solution as well.

As an example, consider an analysis of a penny-shaped edge crack in a larger structure. The large structure is free meshed with C3D10 tetrahedral elements, whereas the structured mesh around the crack uses C3D20 hexahedral elements.

Interaction module: 
   ConstraintCreate: Tie: Constraint enforcement method: Analysis default, Node to surface, or 
   Surface to surface