×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Are you an
Engineering professional?
Join Eng-Tips Forums!
• Talk With Other Members
• Be Notified Of Responses
• Keyword Search
Favorite Forums
• Automated Signatures
• Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

#### Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

# XFEM analysis of thermal fatigue

## XFEM analysis of thermal fatigue

(OP)
Hello, I am quite new to ABAQUS and I am trying to analyze the effects of termal fatigue on the crack initiation and propagation in a 2D unite cell of composite material.

I made a program which calculates the termal stresses induced by the temperature cycles, using temp/disp. coupled elements and another program which calculates the crack front using XFEM technique (mechanical fatigue, plane stress elements). How can I link those two jobs? My idea was to eliminate the load in the second program and insert the temperature in the predefined fields from the first program, and then run again the job; this is not working. There is a more functional way to do it? Is it not posible to use coupled temp/disp. elements for XFEM analysis?

### RE: XFEM analysis of thermal fatigue

if you know the stress in the intact model along the intended crack face, you can apply these stresses to the structural model (or use a handbook solution ... a uniform tension stress along the crack (ie pressure within the crack) is equivalent to a crack in a sheet under remote tension.

Quando Omni Flunkus Moritati

### RE: XFEM analysis of thermal fatigue

(OP)
I don't get how can I apply what you said...

The various parts of the model are expanding or contracting according to their coefficient of termal expansión. I would like to:

1) analyze the fatigue issue due to these cyclic thermal stresses directly using the same ABAQUS program

OR

2) run the programme with the thermal cycles, recover the stress data and implement them in a new "mechanical fatigue" program, which uses stress elements, and not coupled temp/disp. elements.

Which is the best solution? I think the first one woould be better, but it gives me some issues about the time incrementation of the step (I put the cycles of temperatura under "predefined fields" as a table).

### RE: XFEM analysis of thermal fatigue

if 1) means you can get it all done with one model, why not?

i take 2) to mean get thermal displacements from one model and apply them to a structural model, that should work too.

Quando Omni Flunkus Moritati

### RE: XFEM analysis of thermal fatigue

(OP)
I got the model, but results are quite unrealistic since the cracks propagates from the matrix inside the fiber section. Do you know how to describe the interface between fibers and matrix in a 2D unit cell?

#### Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

#### Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Close Box

# Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

• Talk To Other Members
• Notification Of Responses To Questions
• Favorite Forums One Click Access
• Keyword Search Of All Posts, And More...

Register now while it's still free!