r5.03.29 Ductile plastic and viscoplastic damage behavior laws GTN and VISC_GTN

Summary:

This document describes the Gurson—Tvergaard—Needleman ductile damage model (GTN). It is available in a local version and with a gradient of internal variables (GRAD_VARI or GRAD_INCO). The modeling of large deformations is accessible via kinematics GDEF_LOG. The behavior can be independent of time (GTN) or viscoplastic (VISC_GTN). In the latter case, plasticity evolves according to a Norton model in which the threshold function intervenes.

• 1. Field of application
  • 1.1. Purpose
  • 1.2. Material parameters
  • 1.3. Internal variables
• 2. Continuous model
  • 2.1. Behavioral equations: local plastic model
  • 2.2. Taking viscosity into account
  • 2.3. Taking into account the work-hardening gradient
• 3. Digital integration
  • 3.1. Discretized equations in the case without viscosity
  • 3.2. Solving the discretized problem without viscosity
  • 3.3. Solving the discretized problem in the viscoplastic case
  • 3.4. Tangent matrix
  • 3.5. Variables calculated during post-processing
• 4. Bibliography