What are the key considerations for node-to-surface contact?

Node-to-surface contact is a common interaction setup in Abaqus, but improper configurations can lead to issues such as unrealistic stress concentrations or master nodes passing through the slave surface. To ensure accurate and stable results, follow these key considerations:

• Master-slave surface setup
  • Slave surface: Assign the slave surface to the smaller and softer body with higher element density. This ensures that the slave surface conforms better to the master surface.
  • Master surface: Allocate the master surface to the stiffer body (considering both geometry and material properties) and ensure it has a coarser mesh compared to the slave surface.
• Element density
  • The element density of the slave surface should always be higher than that of the master surface. This minimizes issues such as master nodes passing through the slave surface or stress singularities at contact points.
• Geometry and material properties
  • Prioritize assigning the slave surface to the smaller body, as this reduces computational errors and improves contact behavior.
  • If it is not possible to meet all criteria, prioritize mesh density and size over material stiffness when defining master-slave relationships.
• Common pitfalls
  • Master nodes passing through slave surface: This occurs when the master surface has a finer mesh or is assigned to a smaller body. It can lead to unrealistic results.
  • Stress singularities: Concentrated stresses may appear if there are too few interacting nodes due to a coarse slave mesh or improper setup.
• Best practices
  • Refine the mesh on the master surface appropriately if contact stresses are of interest.
  • Use frictionless “hard contact” interactions for simpler setups unless frictional behavior is critical.
  • Conduct sensitivity studies to validate that your setup produces stable and realistic results.