u2.04.01 Tips for using STAT_NON_LINE

Summary

The objective of this note is to give some advice to a user who wants to perform nonlinear calculations with*Code_Aster* using the STAT_NON_LINE [U4.51.03] operator.

General advice is given first. Then we specify the solutions to be implemented for the main types of problems encountered. The problems in question are of the non-convergence type, or failure of an algorithm. Reference is also made to the documentation specific to each problem.

Table of contents

• 1. Introduction
• 2. Convergence tools
  • 2.1. The sub-division of the time step
  • 2.2. The right choice of matrices
  • 2.3. Piloting
  • 2.4. Linear search
  • 2.5. The right choice of the finite element formulation
• 3. Tips common to the 3 types of nonlinearities
  • 3.1. Managing the list of moments
  • 3.2. Load Management
  • 3.3. Managing the convergence of the global nonlinear algorithm
  • 3.4. Archive management
  • 3.5. Observation and monitoring of certain quantities
  • 3.6. Information display and performance
• 4. Material nonlinearity
  • 4.1. Parameters related to behavior resolution
  • 4.2. Management of plastic incompressibility
  • 4.3. Landfill
  • 4.4. Plane stresses
  • 4.5. Damage (softening problems)
  • 4.6. Thermo-Hydro-Mechanical (THM)
• 5. Geometric nonlinearity
  • 5.1. Flambage
  • 5.2. Large deformations
• 6. Contact-friction nonlinearity
• 7. Bibliography