Yesterday, I wrote this but it bounced:
Our good friend, ChatGPT, gave me this when I asked him about the
difference between SOLVE and PSOLVE,Eigen commands when used in ANSYS Modal
Analysis. I hope it helps:
In ANSYS (APDL / Classic) modal analysis, these two commands serve
different purposes and act at different levels of the solution process:
SOLVE
What it does
SOLVE is the high-level command that tells ANSYS to:
1. Assemble the global matrices
2. Call the appropriate solver
3. Compute the requested results (here: eigenvalues and mode shapes)
4. Store the results in the results file (.rst)
In modal analysis
When you issue:
ANTYPE,MODAL
MODOPT,LANB,10
SOLVE
ANSYS internally:
- Forms K (stiffness) and M (mass)
- Solves the eigenvalue problem
( \mathbf{K} - \omega^2 \mathbf{M} ) \boldsymbol{\phi} = 0
- Writes natural frequencies and mode shapes
Key point
SOLVE is the standard and recommended command for modal analysis.
PSOLVE,EIGEN
What it does
- PSOLVE is a lower-level / processor-level solver command
- PSOLVE,EIGEN explicitly calls the eigensolver only
- It bypasses much of the automated solution control done by SOLVE
Typical intent
- Used internally by ANSYS
- Used by advanced users for:
- Debugging
- Custom solution sequences
- Research-level control of solver stages
Limitations
- Does not perform the full solution sequence automatically
- Requires matrices and options to already be correctly set up
- Easier to misuse
- Not documented for routine user workflows
Key point
PSOLVE,EIGEN is not intended for normal modal analysis.
Thanks,
Mohammad A Gharaibeh
The Hashemite University
Yesterday, I wrote this but it bounced:
Our good friend, ChatGPT, gave me this when I asked him about the
> difference between SOLVE and PSOLVE,Eigen commands when used in ANSYS Modal
> Analysis. I hope it helps:
>
> In ANSYS (APDL / Classic) modal analysis, these two commands serve
> different purposes and act at different levels of the solution process:
>
>
> SOLVE
>
> What it does
>
>
> SOLVE is the high-level command that tells ANSYS to:
>
> 1. Assemble the global matrices
> 2. Call the appropriate solver
> 3. Compute the requested results (here: eigenvalues and mode shapes)
> 4. Store the results in the results file (.rst)
>
> In modal analysis
>
> When you issue:
>
> ANTYPE,MODAL
>
> MODOPT,LANB,10
>
> SOLVE
>
> ANSYS internally:
>
>
>
> - Forms K (stiffness) and M (mass)
> - Solves the eigenvalue problem
> ( \mathbf{K} - \omega^2 \mathbf{M} ) \boldsymbol{\phi} = 0
> - Writes natural frequencies and mode shapes
>
>
> Key point
>
> SOLVE is the standard and recommended command for modal analysis.
>
>
> 2.
>
> PSOLVE,EIGEN
>
> What it does
>
>
> - PSOLVE is a lower-level / processor-level solver command
> - PSOLVE,EIGEN explicitly calls the eigensolver only
> - It bypasses much of the automated solution control done by SOLVE
>
> Typical intent
>
>
> - Used internally by ANSYS
> - Used by advanced users for:
> - Debugging
> - Custom solution sequences
> - Research-level control of solver stages
>
> Limitations
>
>
> - Does not perform the full solution sequence automatically
> - Requires matrices and options to already be correctly set up
> - Easier to misuse
> - Not documented for routine user workflows
>
>
> Key point
>
> PSOLVE,EIGEN is not intended for normal modal analysis.
>
Thanks,
Mohammad A Gharaibeh
The Hashemite University
>
