Abaqus Tutorials

eXtended Finite Element Method (XFEM) step by step example for Abaqus Users

XFEM Method in ABAQUS

eXtended Finite Element Method (XFEM)

In this tutorial, we have introduced the extended finite element method or XFEM Metod in Abaqus. You may be wondering what XFEM is?

XFEM Method in ABAQUS?

XFEM is a method in ABAQUS that allows you to study crack growth along an arbitrary, solution-dependent path without needing to re-mesh your model.

See the full definition of XFEM on Wikipedia

this example illustrates the use of XFEM Method in the Abaqus standard solver to predict both crack initiation and propagation due to stress concentration in a plate with a hole that is subjected to tension.

If you want to know more about Abaqus projects, check out Abaqus projects

 

Now, follow the tutorial… 

Part Module

start with creating the part which is two-dimensional and deformable. XFEM Method in ABAQUS

Part Module

start with creating the part which is two-dimensional and deformable.

then create a rectangle with the following dimension.

 

 

create a circle at the middle of the left side with a radius of 0.5

next, create a circle at the middle of the left side with a radius of 0.5. after that, it needs to trim redundant curves.

 

 

 

partitioning of this space can help you to control measuring the part

Hint: partitioning of this space can help you to control measuring the part.

 

 

 

Property Module

create a material with linear elastic behavior. XFEM Method in ABAQUS

in the property module, create a material with linear elastic behavior.

 

 

 

traction-separation behavior of the material using maximum principle stress criteria

then we define the traction-separation behavior of the material using maximum principle stress criteria.

 

 

 

define the damage evolution rule based on energy and linear softening

as you can see in this criterion if the maximum principal stress is positive and more than a critical value the crack initiates and propagates. if the value of this function is between 1 and 1 + tolerance the crack initiation will be considered in the next increments. but if the value is more than one plus tolerance this increment will be solved one more time by cutback.

then define the damage evolution rule based on energy and linear softening. also, use BK (Benzeggagh-Kenan) formulation to calculate effective energy release rate from energy illustrate in various models.

as it is shown in this formula it needs to enter the power.

 

 

 

suboption editor-critical values of G1, G2, and G3

then enter critical values of G1, G2, and G3. also use a stabilization option to simplify the convergence of the standard solver.

 

 

 

create a section and assign it to the part

next, create a section and assign it to the part.

 

 

 

Assembly Module

insert the part in the assembly module. XFEM Method in ABAQUS

then insert the part in the assembly module.

Step Module

create a static general step. Step Module

in the step module, create a static general step.

 

 

 

reduce the initial minimum and maximum size of increments

as the convergence of the problem is not easy due to the propagation of the crack. so reduce the initial minimum and maximum size of increments. also, it needs to increase the maximum number of increments.

increase the maximum number of increments

 

 

 

the sign distance function to describe the correct surface. XFEM Method in ABAQUS

also, request two field outputs related to the enriched elements. the first one is the sign distance function to describe the correct surface. the second one is a state of XFEM elements.

 

 

 

Interaction module

create an XFEM crack and then select the domain

in the interaction module, we create an XFEM crack and then select the domain. here we can also define the initial crack or specify contact properties. But it does not need in this example.

 

 

 

create an XFEM crack and then select the domain in ABAQUS

 

 

Load Module

x symmetry to the left side due to the symmetry of the problem

in the load module, we apply x symmetry to the left side due to the symmetry of the problem.

 

 

 

fixed in y-direction and displacement is applied to the upper edge in this direction

the bottom face is fixed in y-direction and displacement is applied to the upper edge in this direction.

 

 

 

Mesh Module XFEM Method in ABAQUS

a small mesh size in the region with stress concentration

in the mesh module at first, using the seed edge option. apply a small mesh size in the region with stress concentration. we choose the quadrilateral and structured elements and then assign element types to the part.

 

 

 

elements are standard linear. XFEM Method in ABAQUS

elements are standard linear and plain strain finally.

 

 

 

generate the mesh in ABAQUS

next, generate the mesh.

 

 

Job Module XFEM Method in ABAQUS

create the job and submit it

in the Job module create the job and submit it.

 

 

Visualization Module

increase the scale of the formation. XFEM Method in ABAQUS

you can see the initiation and propagation of the crack beside the hole.  for a better presentation of crack opening, you can increase the scale of the formation. you can pull out the contour of PHILSM which shows the distance of points from the crack surface.

 

 

 

XFEM Method For ABAQUS User

 

 

 

XFEM Method in ABAQUS. the status of an enriched element lies between 0 and 1 for correct elements.

the status of an enriched element lies between 0 and 1 for correct elements.

Now download the files and see if you were able to get things done right step by step.

https://drive.google.com/file/d/1Lla7rkQL2ymiyoP_1XxQESep-2LxWkqk/view?usp=sharing


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