How can I apply multiple constraints or loads in a subcase?

Rahul_P1

OptiStruct can only accept one SPC and one LOAD component in a subcase, by default. In other words, multiple load collectors with e.g. different SPC's can't be referenced in the load step panel. There are two ways to apply multiple constraints and loads in a subcase.

1. Put multiple loads in one load collector, and include that one load collector in the subcase. The same method can be used in the case of multiple constraints.

2. Create load collectors for each and every load and constraint set. When you want to apply multiple loads in a subcase, a new load collector needs to be created with the LOAD card (=CardImage=Load). Then, individual load collectors can be combined using the LOAD card. The LOAD card also enables you to associate an independent weighting factor to an individual load collector. In the case of applying multiple constraints, create a new load collector with the SPCADD card (=CardImage), and follow the same procedure as in the multiple load case. Once the combined load collectors are created, they can be applied in a subcase.

alpha_21885

Hi Rahul.

 

Thanks for this useful information. Now I could combine multiple loads(Force, Pressure, Enforced displacement, gravity) to do analysis with Optistruct.

However, do you know how to create 'Subcom' in HM/OS (combines loads but still allow accessbile each load case).

 

Thank you very much.

Rahul_P1

You can use the SUBCOM card in Optistruct,

 

See in help -  OptiStruct > Reference Guide > Input Data > Subcase Information Section > SUBCOM

 

To create it go to analysis > loadsteps > combinatin subcase delimiter

Altair Forum User

hello to everyone, i´m new in the forum and i don´t know if i have to do any presentation for beginning.

 

however, i would like to ask you if it´s possible to put some component (a RBE2) in a subcase, and if yes, how can i do it?

 

thank you

Altair Forum User

Hi @marco pintus

 

I dont think there is a way but I think you can use MPC rigids instead of RBE2 to achieve this. I will check and update to you soon. 

Altair Forum User

Hello, I am struggling with adding load forces (such as water pressure) and gravity forces combined. It seems Hypermesh is only showing 1 of the two.

In load steps; spc 1 i have added constraints (1) and gravity, and in load steps; forces i have added force.

 

What do I have to change?

 

thanks

 

 

Altair Forum User

Hi @Joep

 

Tibi_21537

What about an update for HW 2021.2? There is no card image LOAD!

PaulAltair

Tibi_21537 said:

What about an update for HW 2021.2? There is no card image LOAD!

Today what used to be just 'LOAD' is now called 'LOADADD' (visible in your screenshot) I forget exactly when it changed, but it has been like that for several versions now (change was to add clarity and make it more like SPCADD syntax)