u2.04.04 Instructions for using contact in code_aster

Summary:

This document describes the procedure to be followed for taking into account contact and friction conditions in nonlinear studies. We are interested in surface contact between deformable solids or between a deformable solid and a rigid solid. First, we recall what it means to take into account touch-friction in structural mechanics, then we draw the main lines of a contact problem in code_aster: matching and resolution.

The contact is defined with the DEFI_CONTACT command while the resolution is done with the STAT_NON_LINE or DYNA_NON_LINE commands. Recommendations are formulated for the parametrization of the pairing and the choice of resolution methods in these operators.

Finally, various methodologies are mentioned (contact with a rigid surface, recovering contact pressure during post-treatment, large deformations and contact, rigid body movements blocked by contact,…). They make it possible to overcome the difficulties frequently encountered in studies. In this section, alternative models of the phenomenon of touch-friction by joint elements or discrete elements (through the law of behavior) are also discussed.

Table of Contents

• 1. Introduction
  • 1.1. Purpose of this document
  • 1.2. A vocabulary question
  • 1.3. Alternative contact and friction modeling
• 2. Pairing
  • 2.1. Notion of contact zones and surfaces
  • 2.2. Choice of master and slave surfaces
  • 2.3. Pairing control
  • 2.4. Understanding geometric nonlinearity
• 3. Resolution
  • 3.1. General diagram of the resolution algorithm
  • 3.2. Solving a problem with contact alone
  • 3.3. Solving a problem with friction
  • 3.4. Summary for choosing resolution methods
• 4. Methodologies
  • 4.1. What to do when a contact calculation does not converge or does not converge to the right solution?
  • 4.2. Post-processing of CONT_NOEU
  • 4.3. Recover contact pressure
  • 4.4. Rigid body movements blocked by contact
  • 4.5. Large deformations, large displacements and contact
  • 4.6. Rigid surface and contact
  • 4.7. Redundancy between contact and friction conditions and boundary conditions (symmetry): methods other than LAC
  • 4.8. Measuring interpenetration without resolving contact: methods other than LAC
  • 4.9. View the results of a contact calculation
  • 4.10. Punctual contact with discrete elements (springs)
  • 4.11. (hydro-) mechanical joint elements with contact and friction
  • 4.12. Using adaptive methods
• 5. Bibliography