Optistruct : Enforced displacement tutorial

Hi,

Yes it is possible to run NLGEOM case with enforced displacement in spc definition itself.

See attached deck.

Regards

Rahul R

Unable to find an attachment - read this blog

Thanks for your answer Rahul.

I Created a single SPC definition containing the enforced displacement information and referenced this within the subcase (loadstep) definition and the solver is running...but at the end i am getting 0 results for all the parameters. Can you suggest what could have gone wrong ?

Also pls suggest which control cards i should activate to see the reaction forces ?

Use SPCFORCE card for reaction forces.

I hope you would have provided some value in the field for enforced displacement of constraint panel.

Regards

Rahul R

Thanks for the answer Rahul,

yes i have provided the value. I used a local axis system, created rbe rigid elements and created a node in the middle where i constrained it. I want to analyze it with a 1mm displacement in -z direction .pls refer the attached screen shot. pls suggest if i have been wrong somewhere...

Many thanks

Palash

Thanks for the answer Rahul,

 

yes i have provided the value. I used a local axis system, created rbe rigid elements and created a node in the middle where i constrained it. I want to analyze it with a 1mm displacement in -z direction .pls refer the attached screen shot. pls suggest if i have been wrong somewhere...

 

Many thanks

Palash

Hi

did you switch to 'SPCD' instead of 'SPC'?

yes...

i have total 3 constraints in my geometry...... first constraint is fixed in all directions, second one is free in X direction and third one is an enforced displacement (with rigid elements) in Z direction. I combined the first two in SPCADD card and specified them as 'Subcase_ SPC' in load step. while i defined the enforced dispalcement SPCD as 'SUbcase_LOAD' in loadstep. 

is it correct setup for the problem ?

Regards,

Palash

Yes, but when using SPCD then you must specify those nodes into an SPC in conjunction

I think first and second constraints can be put into same loadcollector (and also SPC nodes of enforcement)

another loadcollector just contains SPCD (it is load)

so you need 2 loadcollectors only, one for SPC, one for SPCD

oh, i am sorry i did not read the first post

you should follow sample file of sir Rahul L because your loadcase is NLGEOM

Hello,

It finally worked....

Thank you Rahul and tinh.....

regards.

Just one more question.....i activated GPFORCE card (in NLGEOM case)...but i am not getting the reaction forces (on enforced displacement nodes) in .h3d file. is there some other card i need to activate for this case ?

HI Palash,

GPFORCE is not supported for NLGEOM subcase.

thanks for your answer Prakash.

so what could be best option for me to view reaction forces in .h3d file ?

regards

Palash,

The workaround is to introduce /ANIM/VECT/FINT in Engine file which will be written in the working directory and run the analysis using RADIOSS solver manager.