modal analysis

[itaranus]

Hello, everyone.

I just started using ansys and can't get good results regarding the problem I describe below:
I imported a set from solid works to workbench 14. all parts of the aid are recognized perfectly and I have no problem with the areas where the parts are in contact! I define a fixed support and get the result of the simulation without any error.

the problem however is that ansys vibrates my structure "trave" around au axis. therefore the vibration is in the direction not from me required.

Imagine drawing a rectangle on the xy plane and then extruding it along the z axis! I want the vibration along the z axis and not around the z axis. In other words it is as if I wanted a vibration due to an orthogonal force on the xy plane. instead ansys simulates the vibration due to an orthogonal force to yz (apply force on the sides of the beam and not above).
You know how I can solve this problem?
Thank you in advance.

 

[Michele1980]

I think you've got some confusion in your head. Can you explain yourself better? You want to make a structure vibrate in a certain way?

 

[gerod]

@itaranus: the presentation is welcome! !
I also understood little while not being a modal analysis expert with ansys (I have seen them years ago, I should give up the topic).
Thank you.

 

[itaranus]

First of all I thank you for the answers.
after which I proceed by presenting myself:
I am a doctoral student (at the third year) of mechatronics at the torino polytechnic. I am doing six months of research abroad at university of southampton (uk) and I have never used ansys in my life. :biggrin:
during this research period in southampton, I was asked to simulate the behaviour and exit of a piezoelectric energy harvester.
I designed the Harvester (it is a multi-layered set made by different sheets) on solidworks and imported on ansys. the result of the simulations were wrong as ansys automatically defined the relationship between the contact surfaces of the plates. By modifying and defining the "connections=>contatcs" properly I get more reasonable results even if not entirely convincing (maybe in some other post I will bring back the problems encountered and I will ask you some advice).
Therefore I think I can say that I have understood what the problem was and why the simulations made were not correct.
in any way I care to thank you for being interested in my problem and for your kindness.
Say hi.

 

[gerod]

Good. Thank you.
It is not that ansys incorrectly defines contacts. I don't want to be wrong, but between options you can also tell him not to put them.