×
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

Beam element stiffness matrix with pin releases

Beam element stiffness matrix with pin releases

Beam element stiffness matrix with pin releases

(OP)
Does anyone know which MSC NASTRAN card outputs the element local stiffness matrix for a single CBAR (12-dof) beam element?  I have a 12-dof beam with some pin (dof) releases and need to run a simple test problem to check the element local stiffness matrix, to compare to some calculations in another analysis.

In case the above won't work, here's the first test problem, in case anyone could cut and paste the 12 x 12 standard stiffness matrix (neglecting transverse shear distortion effects).  Node 1 at (0,0,0).  Node 2 at (-0.7071068,0,-0.7071068).  Element local z' axis lies in global xz plane and points somewhat toward positive z direction.  E = A = L = Iy' = Iz' = J = 1.  Iy'z' = 0.  G = 0.400.  Element end 1 dof 5 (rotation about local y' axis) is released (freed to rotate).

Here's the second test problem.  Same as above except element end 1 dofs 4 and 5 are released (freed), and element end 2 dofs 5 and 6 are released.

If the above won't work (as might be the case in certain programs), then I can change the problem to Iy' = Iz' = 0.08333333.  J = 0.1666667.  (By the way, Poisson's ratio is 0.25.).  Any help is appreciated.

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