×
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

APDL nonlinear stress test - getting error before solution

APDL nonlinear stress test - getting error before solution

APDL nonlinear stress test - getting error before solution

(OP)
hi there friends of APDL,

I was quite a while as a observer in this forum - now I need help and hope somebody would be so kind to discuss my problem with me! I'm an student from germany and for my graduation thesis I'm using APDL v.14.0 for an modal analysis and nonlinear stress test- target is one wing of a windmill ( CK220 http://www.windenergie-technik-crome.de/ProfilCK22...).

First I build my model bottom up and could succesfully do a modal analysis. The first 8 frequencies look allright,I've done measurements FFT so I have values to compare. Ansys says total mass is 5,6kg which exactly represents my orignial wing :)

Well after that my task was to compare another "stress" measurment. I pushed the wing with a newton meter and recorded the actual displacement from my push. I stayed in the linear area so I can assume Hooke's Law is valid. (range 10- 40 N, example : 30N-4mm)

"The value of ROTX at node 2356 is 2917362.35. It is greater rhan the current limit of 1000000. This generally indicates rigid body motion as a result of an unconstrained model. Verify that your model is porperly constrained."

I guess I have no rigid body motion. There is contact between my two materials (always bonded) but my first frequency is at 62Hz.

Where do i have to go from here? I also use SOLID72 with doesnt support "large deflection" is this important?
My last idea is convergency.

- increase pinball radius at contact
- decrease contact stiffness at contact
Do i need to change this at every contact?

And maybe change the properties of convergency?
- NSUBST up
- DELTIM down

Put my code into attachments if needed I can post my ansys output too.

Would appreciate any suggestions since I'm only since 2 months into APDL :)

Best regards
Eugen

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