PSOLVE

PSOLVE, Lab
Directs the program to perform a partial solution.

SOLUTION: Analysis Options

Lab

Valid labels defining the solution step. All characters are required:

EIGDAMP	—	Calculates the eigenvalues and eigenvectors using the damped eigensolver. Requires Jobname.full from MODOPT,UNSYM or MODOPT,DAMP options. Produces Jobname.mode.
EIGQRDA	—	Calculates eigenvalues and eigenvectors using the QR damped eigensolver. Requires Jobname.emat from MODOPT,QRDAMP option. Produces Jobnamemode.
EIGEXP	—	Expands the eigenvector solution. Requires Jobname.esav and Jobname.mode. Produces Jobname.rst.
EIGLANB	—	Calculates the eigenvalues and eigenvectors using Block Lanczos. Requires Jobname.emat from MODOPT,LANB option. Produces Jobname.mode.
EIGLANPCG	—	Calculates the eigenvalues and eigenvectors using PCG Lanczos. Requires Jobname.emat from MODOPT,LANPCG option. Produces Jobname.mode.
EIGSNODE	—	Calculates the eigenvalues and eigenvectors using the Supernode method. Requires Jobname.emat from MODOPT,SNODE option. Produces Jobname.mode. (See the MODOPT command for more information on the SNODE modal solver.)
EIGUNSYM	—	Calculates the eigenvalues and eigenvectors using the unsymmetric eigensolver. Requires Jobname.emat from MODOPT,UNSYM or MODOPT,DAMP options. Produces Jobname.mode.
ELFORM	—	Creates the element matrices. Produces Jobname.emat and Jobname.esav. Note: If you want to include prestress effects (PSTRES,ON) from a previous prestress analysis, the ELFORM option requires the Jobname.emat and Jobname.esav files generated by that analysis.

Notes

Directs the program to perform a partial solution (that is, one step of an analysis sequence). Predefined analysis types (ANTYPE) perform a defined subset of these solution steps in a predefined sequence. You can use the partial-solution procedure to repeat a certain step of an analysis or to restart an analysis.

Not all steps are valid for all analysis types. The order of the steps may vary depending on the result you desire. See the Basic Analysis Guide for a description of how to perform partial and predefined solutions.

An example of a prestressed modal analysis is given below. The Jobname.emat and Jobname.esav files from a prior static analysis must be available.

The example is provided for illustration purposes only, as the linear perturbation analysis method is recommended in place of this partial-solution method.

! Prestressed modal analysis
!
/SOLU
ANTYPE,MODAL       ! Modal analysis
UPCOORD,1.0,ON     ! Display mode shapes relative to deformed geometry 
                   !   in the postprocessor.
PSTRES,ON          ! Prestress effects ON
MODOPT,LANB        ! Select eigensolver
PSOLVE,EIGLANB     ! Calculate the eigenvalues and eigenvectors.
                   ! EIGxxx label must be consistent with mode extraction method on MODOPT command.
FINISH
/SOLU              ! Additional solution step for expansion.
EXPASS,ON
MXPAND,...         ! Specify the number of modes to expand, if desired.
PSOLVE,EIGEXP      ! Expand the eigenvector solution. (Required if you
                   !   want to review mode shapes in the postprocessor.)
FINISH

In a cyclic symmetry analysis, PSOLVE,EIGLANB or PSOLVE,EIGLANPCG performs the modal analysis at multiple load steps, one for each nodal-diameter specified via the CYCOPT command. In addition, the eigenvector solution is expanded at each nodal-diameter solution, eliminating the need for a separate expansion pass (PSOLVE,EIGEXP).

If Jobname.emat is required, run the prior analysis with EMATWRITE,YES to ensure that a Jobname.emat is generated.