13.1. Including Debonding in a Contact Analysis

Debonding can be defined in any model that includes surface-to-surface (CONTA172 and CONTA174), node-to-surface (CONTA175), line-to-line (CONTA177), or line-to-surface (CONTA177) contact. For a detailed discussion on how to set up a contact analysis, see Surface-to-Surface Contact (Pair-Based).

To activate debonding for a contact pair, the following contact options must be defined for the contact element:

  • Augmented Lagrangian method or pure penalty method (KEYOPT(2) = 0 or 1)

  • Bonded contact (KEYOPT(12) = 2, 3, 4, 5, or 6)

In addition, you must specify a cohesive zone material (CZM) model. Several bilinear models and an exponential model are available.

The following bilinear models are exclusively for contact elements:

  • Bilinear material behavior with tractions and separation distances (TB,CZM command with TBOPT = CBDD)

  • Bilinear material behavior with tractions and critical fracture energies (TB,CZM command with TBOPT = CBDE)

These bilinear models are recommended for contact debonding. However, the following bilinear and exponential models initially developed for interface elements can also be used with contact elements:

  • Bilinear material behavior with tractions and separation distances (TB,CZM command with TBOPT = BILI)

  • Exponential material behavior (TB,CZM command with TBOPT = EXPO)

These material models are described in the following section.

Once you have defined the required input parameters, you can solve the analysis the same as you would for any nonlinear analysis (see Solving the Problem).

After debonding is completed, the surface interaction is governed by standard contact constraints for normal and tangential directions. Frictional contact is used if friction is specified for contact elements.