×
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

Get angular velocity on a node (or element extremity)

Get angular velocity on a node (or element extremity)

Get angular velocity on a node (or element extremity)

(OP)
I'm using the parametric design language to model a dynamic problem using the BEAM54 element.
I need to take the angular (or rotational) velocity in some nodes to use them as initial conditions.
I can do it in the graphical user interface, using the "list results" option of the pos-processor.
But I need to do it automatically, in the same way you can get displacement velocities using v_y("node number") and storing them in a vector.
I searched in the *GET command help file, to no avail.

RE: Get angular velocity on a node (or element extremity)

We can't get angular velocity directly,but we can get angular displacement over time,and then differentiate this curve to get angular velocity.

RE: Get angular velocity on a node (or element extremity)

(OP)
Thanks for your answer.
Since I'm using lots of substeps and storing the results only for the last one, I'm not sure it would give accurate results in my case, but its a good idea, I could even ask for the complete solution for all the substeps, do the necessary calculations, and then output results only for the last substep of each step.

Meanwhile I found another way to do it.
What I did was use the PRNSOL command (equivalent to the "list results" option), but directed the output to a txt file.
After that I read the file to a array, and its done.
The commands I used were:

/HEADER,OFF,OFF,OFF,OFF,OFF,OFF !turn off the headers
/PAGE,nelem+2,,nelem+2 !defines the number of lines per page
/FORMAT,15,E,15,10,    !defines the format (exponential)
/output,omgz1,txt      !redirects output to "omgz1.txt"
PRNSOL,OMG,Z           !lists the desired results
/out                   !end of output statement

*dim,omg,array,nelem+1,2  !creates the array
*VREAD,omg,'omgz1','txt',,IJK,nelem+1,2,1,2,  !reads the file
(2E16.10)

Its not terribly efficient from the computational side, but it minimizes the need for additional calculations and the code is short.

Thanks again for your time, its very difficult to get answers to these very specific problems.

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