## General Mechanical

Topics relate to Mechanical Enterprise, Motion, Additive Print and more

#### restriction of degrees of freedom

• Massochy dos santos Ventura
Subscriber

I'm doing a modal analysis on a free-free steel plate and want to restrict UX,UZ,ROTX,ROTY and ROTZ on all nodes before running the solution and then extracting the vectors

• Ashish Kumar
Forum Moderator

Hi,

Use D command.

Regards,

Ashish Kumar

• Massochy dos santos Ventura
Subscriber

I used this command and the following information appears but without a solution

D ,All,UX,UZ,ROTX,ROTY,ROTZ,0,

• Massochy dos santos Ventura
Subscriber

Do you have an example of a D command to restrict degree of freedom on all nodes

• Ashish Kumar
Forum Moderator

Hi,

You can refer to the following VM: VM244 Input Listing (ansys.com)

Regards,

Ashish Kumar

• Massochy dos santos Ventura
Subscriber

Estou trabalhando com 25 nós e usei este código

CSYS, 1

D, TODOS, UX

D, TODOS, UZ

D, TODOS, ROTX

D, TODOS, ROTY
D, TODOS, ROTZ
NSEL, TODOS
ACABAR

e eu tinha uma matriz 25 * 25 por ser o número de nós vezes o grau de liberdade, mas eu tenho frequências naturais iguais a zero em todos os modos. Eu gostaria de saber se este resultado está correto

• Mike Rife
Ansys Employee

Hi Massochy

This command is not quite correct:  D ,All,UX,UZ,ROTX,ROTY,ROTZ,0,

Please see the MAPDL Command Help entry on the D command for the description of the commands fields.  But most likely you wanted:  d,all,ux,0,,,,uz,rotx,roty,rotz

Mike

• Massochy dos santos Ventura
Subscriber

I wonder if with these commands I can restrict the degrees of freedoms??

• Mike Rife
Ansys Employee

What do you mean by restrict?

• Massochy dos santos Ventura
Subscriber

I'm doing a modal analysis on a free-free steel plate in order to extract stiffness matrix, mass matrix and the vectors corresponding to the vibration modes for each natural frequency. in order to reduce the values ​​of the matrices so I intend to restrict some degrees of freedom all nodes since the matrix is ​​formed by the multiplication between numbers of nodes and the degrees of freedom (in this case they are 6)..