Element Deletion

In the steps that follow, we'll use the HIN file to define our criterion for deleting elements. There are three element deletion criteria available for woven materials, all of which use the TYPE=FIBER. There is no matrix type criteria available for woven composites. Let's take a closer look at each option.

TYPE=FIBER, CRIT=ANY

For the CRIT=ANY case, an element is triggered for deletion if the fiber fails in either tow.

TYPE=FIBER, CRIT=BOTH

For the CRIT=BOTH case, an element is triggered for deletion if the fiber fails in both tows.

TYPE=FIBER, CRIT=RELOAD

For CRIT=RELOAD, stresses in the tow direction are monitored following a fiber failure. The normal stress in the failed tow direction, σ_n, is compared to the ultimate tensile strength in the failed tow direction, S₁₁^U. If the ratio of σ_n to S₁₁^U exceeds a user specified value β, the element is deleted. β is specified on the first data line following the *ELEMENT DELETION keyword. For example:

*ELEMENT DELETION, TYPE=FIBER, CRIT=RELOAD
0.3

In this example, if σ_n meets or exceeds 30% of S₁₁^U following a fiber failure, the element is deleted. The RELOAD criterion also includes the logic of the BOTH criterion, so that a fiber failure in both tows would also trigger the element to be deleted.

Back to the Tutorial

For our tutorial, we will control element deletion using CRIT=BOTH.

1. Use a text editor to create a HIN file named Tutorial_6_PW_Abaqus.hin
2. Add the following lines to the file:

   *MATERIAL, NAME=DMS2288-epoxy
   *ELEMENT DELETION, TYPE=FIBER, CRIT=BOTH

3. Save the file

Practice

For some additional practice with the element deletion criteria, try using the following settings:

*ELEMENT DELETION, TYPE=FIBER, CRIT=ANY

*ELEMENT DELETION, TYPE=FIBER, CRIT=RELOAD
0.2

Tip: Copy the existing input file and HIN file and rename them. Modify the HIN file for each case above and run the analysis. We will explore all of the results later.