r7.07.01 Limit load calculation using the Norton-Hoff-Friaâ method, behavior NORTON_HOFF

Summary:

Limit analysis makes it possible to determine the allowable loads of a structure, with a given fixed geometry, made of a material having a resistance criterion. We consider the case of loads consisting of the sum of a permanent load and another parameterized by the load factor, whose extreme bearable value is sought.

After a review of the theoretical formulation, the regularized kinematic approach applied to the VonMises resistance criterion (Norton-Hoff-Friaâ method) and implemented in Code_Aster is presented. Refer to [bib4] for the various possible regularization methods proposed in the literature. The calculation of the solutions to this nonlinear problem is then presented and the post-processing providing an estimate of the limit load (an excess value in all cases, and when there is no permanent load, a value by default) is presented.

Table of Contents

• 1. Theoretical formulation of limit analysis
  • 1.1. Definition of limit load
  • 1.2. Calculation of the limit load using a kinematic approach
  • 1.3. Regularization of the kinematic approach by the Norton-Hoff-Friaâ method
• 2. Numerical aspects of limit load calculation
  • 2.1. Norton-Hoff behavior relationship
  • 2.2. Piloting
  • 2.3. Post-processing of the limit load calculation
• 3. Features and verification
• 4. Bibliography
• 5. Description of document versions