Multiple Load Cases in Abaqus

[VN1981]

Hello,
I am wondering how to accomplish the below in Abaqus Standard/CAE.

Lets say I have a structure (aircraft interior monument) and I want to analyze the above structure for different emergency inertial factors (Forward 9.0g, Aft 3.0g etc). The loading is input as inertial (I need to check the correct term in Abaqus CAE). And I may need to perform non-linear (geometrical) analysis. In FEA packages similar to Abaqus, I can create multiple load cases and assign a different job card for each case and analyze all of these load cases simultaneously but independently. And I can post-process each of the above load cases in the same FEA session (i.e. all the results from different load cases will be contained in one single output file).

I realize that I can create load cases for Static Perturbation step but I believe only linear analysis is supported by the above function.

Any inputs on how I can accomplish load cases in Static General step?

I can create 4 separate steps but I am afraid that subsequent steps may use conditions or state of the structure from the previous steps. Am I correct in understanding how steps work in Abaqus? I want each load case to be independent of each other and start at original state (undeformed).

 

[testing]

If you use the "OP=NEW" option when defining loads and boundary conditions for each steps, it should reset rather than carry over previous definitions.

 

[VN1981]

Thanks. Is there any way the above can be specified in the GUI rather then entering keywords manually?

 

[testing]

Probably, but I don't work in the GUI much, so I can't help you there. Shouldn't be hard to modify the .inp that gets written out though.

 

[VN1981]

Where in the input file would I specify the above keyword? Step definition?

 

[testing]

It's an option on your loading and BC keywords, not a standalone keyword. So it'd look something like *CLOAD, OP=NEW

 

[Mustaine3]

When the behavior is nonlinear, then the steps built up on each other. So using OP=New is only ok when the effect from the previous step disappears in the next one. If you have plasticity or other path dependent behavior, then you can't do that.

You have to run the jobs independent of each other in separate analysis.
If you have a preload step that is common for all, then you can use *Restart to start a new analysis with the specific configuration of another analysis.