×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*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.

Students Click Here

Jobs

Hello to all, I'm trying to perf

Hello to all, I'm trying to perf

Hello to all, I'm trying to perf

(OP)
Hello to all,

I'm trying to perform a simulation of a 3 points bending test on a composite material (made of 6 plies). I'm using NX/NASTRAN with solver 106 601. I have some problems with the results, they aren't congruents.

First at all I start with describing the FEM model. In according with the image just below, I used shell elements (CQUAD8) for the specimen, the 2 supports and the impactor. The supports are constrained in all translations and rotations (all fixed), the impactor is constrained in x,y,Rx,Ry,Rz and an enforced motion is applied in z direction (vertical axis), and the surface of the specimen has been divided in the middle (by using a divide face in the idealized part) and the center line (generated by the divide face) has been constrained in x,y,Rx,Ry,Rz (the translation in z direction is free). Contacts between specimen and supports and impactor have been defined.



NASTRAN can solve the model, but I have problems with the results. Below a picture of the displacements (magnitude), it is possible to see that they are symmetrical and this is right :



But the stresses of each ply are note axys-simmetrical and this is wrong because the impactor is exactly in the middle of the specimen :



I don't know why I have this error, maybe the material is not well defined but I checked and all look fine.

Thank you in advance for your help,
Best regards

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.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources