Understanding Steps and Substeps

[MechanicalEngineer20]

I am a new ANSYS user as well as new to Finite Element Analysis in general. I am having difficulty grasping the concept of steps and substeps. I tried searching for answering online, but could not find any sources that directly spelled out and helped me understand what substeps are.

As far as my understanding goes, a step is just a percentage of the applied load. For example, I could have 10 steps in total and start on the 5th step and end of the 6th step and that would apply 50-60% of the load correct?

My second question is dealing with ANSYS the "Define By" option under "Analysis Settings." When switching from program controlled to define by substep, what does initial, minimum and maximum substeps mean? Is this just the set amount of substeps in between the set steps I chose in the "Step Controls" option?

Thank you for your help.

 

[ZeroExperience]

Try looking up "linear perturbation" when looking up Ansys documentation.

I don't know how Ansys does it, but this is how MSC Nastran does it and may be similar to how Ansys does it.

MSC Nastran uses a "SUBCASE" and "STEP" approach. For example, say I want to perform a nonlinear static analysis followed by a complex modal eigenvalue analysis at various point through out the loading, say 10%, 50%, and 100% of the applied load. The layout is as follows.

SUBCASE 1
STEP 1
ANALYSIS=NLSTATIC
STEP 2
ANALYSIS=MCEIG
you would define 10% of the load here.
STEP 3
ANALYSIS=MCEIG
Define 50% of the load here.
STEP 4
ANALYSIS=MCEIG
DEFINE 100% of the load here.

In Step 1 the nonlinear static is performed, the resulting state of the body is then carried over to STEP 2,3, and 4. This is known as analysis chaining.