×
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

How to obtain the natural frequency of the beam in ANSYS

How to obtain the natural frequency of the beam in ANSYS

How to obtain the natural frequency of the beam in ANSYS

(OP)
Dear gentlemen,

   I am new in ansys, and I need a help. I want to obtain the frequencies of the beam, for any properties of the beam and any boundary conditions. I need some example how to set parameters of the beam, number of finite elements. Of course, for the beginning I need analyze for free vibration of the beam. We can include rotary inertia and shear. But for the beginning. ANSYS, frequency, settings parameters and boundary conditions.

Regards!!!

Georg  

RE: How to obtain the natural frequency of the beam in ANSYS

There is a tutorial in the ANSYS help file that covers modal analysis of an airplane wing (which is like a beam). Drill down through the tree on the LHS of the help menu and select: "ANSYS Help System > Mechanical APDL > Tutorials > 8. Modal Tutorial > 8.1 Modal Analysis of an Airplane Wing"

Of course, you could use beam elements as well, but I'd imagine that your model won't be very large either way.

Good luck.

//signed//
Christopher K. Hubley
Mechanical Engineer
Sunpower Incorporated
Athens, Ohio
--
http://engineeringliberty.wordpress.com

RE: How to obtain the natural frequency of the beam in ANSYS

This should get you started. You can parameterize any value in the commands.

CODE

fini
/cle,nostar

/title,Modal Analysis of a Simply Supported Beam
/filnam,beam_modal

/prep7

! ============== PARAMETERS ==================
YOUNGS_MOD = 210e9
SHEAR_MOD = 210e9/2.6
POISSON = 0.3
DENSITY = 2400
ELEMENT_SIZE = 5/100
KP_COORDX1 = 0.
KP_COORDX2 = 5.0
! ============================================

mp,dens,1,DENSITY
mp,ex,1,YOUNGS_MOD
mp,nuxy,1,POISSON
mp,gxy,1,SHEAR_MOD

k,1,KP_COORDX1,0.,0.
k,2,KP_COORDX2,0.,0.

l,1,2

et,1,4
r,1,0.5,4.17E-2,10.42E-3,0.25,0.25,,
RMORE, , ,0.83, , , ,   

lesiz,all,ELEMENT_SIZE
latt,1,1,1
lmesh,all

alls

/solu
DK,1,,0.,,0,UX,UY,UZ ,rotx ,roty , ,
DK,2,,0,,0,UY,UZ ,rotx ,roty , , ,  
alls
d,all,uz,0.
d,all,rotx,0.
d,all,roty,0.

ANTYPE,2
MSAVE,0
MODOPT,LANB,5   
EQSLV,SPAR  
MXPAND,5, , ,1  
LUMPM,0
PSTRES,0
MODOPT,LANB,5,0,0, ,OFF

alls
solv
save
fini
/post1


------------
See FAQ569-1083: Asking questions the smart way on Eng-Tips fora for details on how to make best use of Eng-Tips.com

RE: How to obtain the natural frequency of the beam in ANSYS

(OP)
Dear Drej

Thank you very much for this code. But where can I type this code and I wanted to change something (dimension of the beam) and obtain then the eigenvalues problem? How. If you have some .pdf manual for example, very simple.

Thank you in advance!!!

RE: How to obtain the natural frequency of the beam in ANSYS

You can read this code in using File -> Read Input From -> and then choose the file that this code contains. The beam properties can be changed using the real constant in the code. Sounds like you will need to take some time to learn ANSYS and APDL, but most importantly (before you start punching numbers) understand modal analysis. There are many examples available across the web and also within the ANSYS online manual (the post above is a good start).


------------
See FAQ569-1083: Asking questions the smart way on Eng-Tips fora for details on how to make best use of Eng-Tips.com

RE: How to obtain the natural frequency of the beam in ANSYS

(OP)
Dear Drej,

 It is clear, but where I can set the boundary conditions, dimensions of the beam in your file? Also I would like to get the natural frequencies for free vibrations.

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