Jump to content

Recommended Posts

Hello,

 

I would like to perform a modal analysis of a helicopter blade while it is rotating at a constant RPM.

 

I have created two steps in hyper-mesh, first is a linear static with boundary conditions and applied a centrifugal force with the RFORCE card.

Second step is a normal modes step with the previous step linked through the STATSUB card and no boundary conditions or forces selected (free-free) modal analysis.

 

Whenever i run this, the first step works, however i get an error:

 

*** ERROR #  15 ***
 CTETRA element 252760 is distorted (zero or negative Jacobian).
  

I checked my mesh and i have no issues with the Jacobian or mesh at those indicated elements.

As a check, i've run both steps separately and both work and give good results. 

 

I don't know if this is the right way to perform such an analysis where the blade stiffness is changed by the centrifugal loading due to rotation.

 

Your help is appreciated.

 

Kind Regards,

Mohamed

FinalModel_01-12-2016_Finalzed_model_Pre_stressed_modal.hm

Share this post


Link to post
Share on other sites
Guest

Hi Mohamed,

 

Which version of HyperWorks are you using?

 

I don't see the error you posted when I used the model file you shared in HyperWorks 14.0. Instead I see a different error and that is because your laminate has only one ply which is very thin. 

 

Kindly update to HW 14.0 and try again :)

 

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
You are posting as a guest. If you have an account, please sign in.
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...