The extended finite element method (XFEM) is a powerful technique that allows you to study the onset and propagation of cracking in quasi-static problems without needing to remesh your model. XFEM is available only for three-dimensional solid and two-dimensional planar models; three-dimensional shell models are not supported. You can use XFEM to study a crack in parts containing geometry, orphan mesh elements, or a combination of the two. You can choose to study a crack that grows arbitrarily through your model or a stationary crack that cannot grow.
In this article, we will show you how to create a stationary XFEM crack in Abaqus using the Interaction module. You will need to specify the following:
Crack domain: The region that contains any existing cracks and regions in which a crack might be initiated and into which a crack might propagate.
Crack location: The initial position of the crack within the crack domain. You should not select a seam crack.
Enrichment radius: The radius from the crack tip within which the elements will be used for calculating crack singularity.
The steps are as follows:
From the main menu bar in the Interaction module, select Special > Crack > Create.
From the Create Crack dialog box that appears, select XFEM. Enter the name of the crack, and click Continue to close the dialog box.
From the model in the viewport, select the entities representing the crack domain. You can select cells from a three-dimensional part instance or faces from a two-dimensional part instance. If you have an orphan mesh or an instance containing both orphan mesh and native mesh elements, you can select elements to represent the crack domain. Click mouse button 2 to indicate that you have finished selecting the crack domain.
The Edit Crack dialog box appears. Toggle off Allow crack growth to define a stationary crack that cannot grow.
Click to specify the crack location by selecting interior faces from a three-dimensional model or edges from a two-dimensional planar part.
To specify the enrichment radius, do either of the following:
Choose Analysis default, to allow Abaqus to determine the enrichment radius. The default radius is three times the typical element characteristic length in the enriched area.
Choose Specify and enter a value. The value should be the radius from the crack tips within which the elements are used to calculate the crack singularity.
Choose the type of XFEM analysis: By default, Abaqus will use the traction-separation cohesive behavior approach. You can select or create a contact interaction property that specifies the compressive and frictional behavior of the cracked faces based on a small-sliding contact formulation. For more information, see Defining surface-to-surface contact.
Click OK to create the XFEM crack.
You have successfully created a stationary XFEM crack in Abaqus. For more information on XFEM, see The extended finite element method (XFEM). aa16f39245