The Create Cohesive Material plug-in defines the complete material response for a Simulation Composite Analysis cohesive material.
Specifically, the material stiffnesses, tractions, and damage initiation and softening type are defined. You have several options to define the damage response of the cohesive material.
- The Initiation Criterion defines the method for determining the initiation of failure in the cohesive element. Maximum Stress and Quadratic Stress are the available options.
- The Softening Type option defines the method for computing the reduction in stiffness of the element after failure has been initiated. Displacement, Energy, and Mixed Mode Energy are options.
- For complete details on these material options, refer to the Theory Manual.
For this example, the Maximum Stress damage initiation and Energy based damage evolution criteria will be used since the DCB specimen is loaded in pure mode I.
There are many different approaches for determining cohesive material properties. The properties below are for demonstration purposes and a full discussion of their determination is beyond the scope of this document. For a detailed discussion of cohesive properties and a recommended method for determining their values, refer to the Energy-Based Material Degradation section of the Theory Manual.
In the following steps, a user-material is defined using the Create Cohesive Material plug-in.
- Click the COMPOSIT button and click Create Cohesive Material in the dialog that appears.
- Give the cohesive material an ID of 102.
- Enter 1.0E+11 for Knn, Kss, and Ktt, 1.0E+05 for Sn, and 3.0E+05 for Ss and St.
- Select the Maximum Traction Initiation Criterion and Energy Softening Type
- Enter a Fracture Energy of 0.01.
- The dialog should now appear as shown below. Click OK to create the material.
