Formulate equations in MPC bulkdata entry

Vikas_22008

Hi

In a model, I have 2 contacts and 2 different load cases. For one load case, i just need one of the contacts to activate and for the other load case, I want another contact to activate. I learned that this can be achieved by using 'MPC bulk data entry in the load steps'. I would like to know how to define the equations for the displacements. 

I need the part to move in +y direction during one of the load cases and -y during other load case. No movment in x or z direction.

Thanks in advance

 

Regards
Vikas M B

Rajashri_Saha

Hi Vikas,

For activating and deactivating CONTACTs you can use MODCHG option.

Refer the below links for more information and example file.

https://help.altair.com/hwsolvers/os/topics/solvers/os/subcase_specific_model_change_using_3_rings_os_example_r.htm

https://help.altair.com/hwsolvers/os/topics/solvers/os/modchg_bulk_r.htm?zoom_highlight=modchg+tutorial

Regarding displacement application, you need to create two loadsteps. In 1st loadstep you can constrain in X, Z translation and apply displacement through SPC by specifying value say 5mm in +ve Y-dir (see the image). In second load step your constraint will be again X, Z translation and apply displacement load in -ve Y-dir.

Thanks

Rajashri

Vikas_22008

Hi Rajashri,

thanks you for the response. 
I would like to do a linear analysis with the contacts not non linear analysis. For that I need to know how to form the equations in MPC bulkdata(see the image). If I could create 2 MPC bulkdatas, then I could use it in the loadcases.

I do not understand this. I read the guidelines but that doesn't give me any hints on how to form equations. 

Regards

Vikas