Contact problem between a rotor blade and his attach 1

[agash]

Hi evryone.

Im new with abaqus and i badly need your experience.
Let me explain you my problem,i have to find the eigenfrequency of a blade wich is attach in a rotor.
So first of all,in a first step (static),i modélise a force on the bottom of the blade to represent de centrufuged force then in a second step (natural frequency),im trying to get those eigenfrequency,but my problem is:
The master surface enter into the slave surface.
I tried to fix all the contact process but there is still a pénétration of a surface into another.
Can you please have a look on my INP file because more than words an example explain it more.?
i spent more than a week on that simple modélisation before starting a complex problem but im not able to achieve it properly and im starting to desesperate.
thanks in advance

 

[akabarten]

Hello Agash,

During eigenfrquency analysis a solver does not use any contact features. The contacts defined in first step are ignored in natural frequency step.
To simulate connection between separate bodies in the model you have to use constrains options. In your case you can remove *CONTACT PAIR from your model and use *TIE (with the same surfaces as *Contact Pair) instead.

Regards,
akaBarten

 

[agash]

Thanks akabarten for quick reply.
It was clear.
So if i sumup,during eigenfrequency calcul the solver doesnt use the contact which was made by the load in the step one?
In fact i have find eigenfreqency as the experimental test where the blade was constrain with th attach with a load on the bottom.
According to you,is there a difference (eigenfrequency) if i modelise the blade alone with proper test boundary condition and the blade+attach with the tie constrain as u said?
Thank alot

 

[akabarten]

Hi,

>>> According to you,is there a difference (eigenfrequency) if i modelise the blade alone with proper test boundary condition and the blade+attach with the tie constrain as u said?

For these two cases you should get different values. The values of eigenfrequency depend on stiffness assembly and mass distribution. If you use model made of a blade and boundary conditions you will loose information about stiffness and mass distribution of the second part.

Regards,
akaBarten

 

[agash]

Thanks,i learned alot.
So in my inp file that i sent before,in the animation i can see faces sliding for each mode,but i put contact properties between faces and it ran my probleme,thats what i dont get, if the solver doesnt use CONTACT,how did he solved the probleme and gave me the displacement of each mode?
Im confused
if you can,can you have a look on my file,because i have to expose my problem on monday and doesnt wanna say a stupidity as its my first month of job.

thanks again

 

[akabarten]

Hi,

Can you sen me a file for my mail: barten@go2.pl

Thanks.