r5.03.80 Load control methods

Summary:

This document describes the load control methods available in Code_Aster (by a degree of freedom, by arc length, by deformation increment, and by elastic prediction). They introduce an additional unknown, the intensity of the controllable part of the load, and an additional equation, the control constraint. In particular, these methods make it possible to calculate the response of a structure that would present instabilities, both geometric (buckling) and material (softening).

• 1. Introduction
  • 1.1. Nonlinearity and Newton’s failure
  • 1.2. Problems with unknown load intensity
• 2. Principle of load control methods
• 3. Global system resolution
• 4. Piloting control equation
  • 4.1. Control by controlling a degree of freedom of movement: DDL_IMPO
  • 4.2. X-FEM modeling control by controlling the movement jump in one direction: SAUT_IMPO
  • 4.3. Control by arc length: LONG_ARC
  • 4.4. X-FEM modeling control by controlling the displacement jump standard: SAUT_LONG_ARC
  • 4.5. Control by the deformation increment: DEFORMATION
  • 4.6. Piloting through elastic prediction: PRED_ELAS
• 5. Bibliography
• 6. Description of document versions