Alter to perform dynamic reduction using the Improved Reduced System
(IRS) method.



Alter Name    irsa.alt


Purpose

To perform dynamic reduction using the Improved Reduced System (IRS)
method.

Solution Sequence

SOL 103.


Input

Executive Control

Include 'irsa.alt'
 
Case Control

None.
 
Bulk Data

ASET entries to specify the reduction locations.  

Output

Standard 103 output.


Limitations

Superelements are not supported.


Sample Files

irs1.dat      Sample plate problem using the IRS reduction
              method.

irs2.dat      The same sample plate problem using Lanczos
              without reduction.


Additional Documentation

1.  Flanigan, C., "Implementation of the IRS Dynamic Reduction
    Method in MSC/NASTRAN", The MSC 1990 World Users Conference
    Proceedings, University City, California, March, 1990.

2.  O'Callahan, J., "A Procedure for an Improved Reduced System
    (IRS) Model," Proceedings of the 7th International Modal
    Analysis Conference, Las Vegas, Nevada, February, 1989.