Program: SAP IV

Donwload: Sap4 Source Code

Title: Static and Dynamic Response of Linear Systems

Developer:  K-J. Bathe, E.L. Wilson and F. E. Peterson,
Department of Civil Engineering, University of California,
Berkeley 1973

Modified: B.F. Maison, Structural Engineer, El Cerrito, California 1992.

Category:  Structural

Platform: CDC,Scope,FTN4 (60 bit single precision);
          IBM,VM/CMS,Fort4H (double precision);
          VM/CMS Fujitsu VP;
          PC DOS, Lahey F77L-EM32 Fortran

Reference: Bathe, K.-J., E.L. Wilson, and F.E. Peterson,
"SAP IV-Structural Analysis Program for Static and Dynamic
Response of Linear Systems," Earthquake Engineering Research
Center, Report No. UCB/EERC-73/11, University of California,
Berkeley, June 1973, revised April 1974.

Maison, B.F., "PC-SAP4 -- A Computer Program for Linear Structural
Analysis," August 1994.

Summary: SAP IV is a finite element structural analysis program for
the static and dynamic response of linear three-dimensional systems.
The program is written to analyze structures which are idealized by
combinations of structural element types. The capacity of the problem
depends mainly on the number of finite element nodal points in the system.
There is practically no restriction on the number of elements, the number
of load cases and the number or bandwidth of the equations to be solved.

In a dynamic analysis the options are: (1) frequency calculations,
(2) frequency calculations followed by response history analysis, (3) frequency
calculations followed by response spectrum analysis and (4) response history
analysis using step-by-step direct integration. Despite large system capacity,
no loss in efficiency is encountered in solving smaller problems. The report
describes the logical construction of the program, the dynamic high speed
storage allocation, the analysis capabilities, the finite element library and
the numerical techniques used.

The following element types are available: Three-dimensional truss, Three-
dimensional beam, Plane stress and plane strain quadrilateral, Two-
dimensional axisymmetric solid, Three-dimensional solid (8 node brick),
Plate and shell quadrilateral, Boundary element, Three-dimensional straight
or curved pipe element, Variable number of nodes thick shell and 3-D element.

Comment: No sample inputs or outputs are available for the HP version.

Some hints on converting PC-SAP4 for the Lahey Fortran90 compiler from
Dr. Barry Santana, 7 Nov 98.

1.  There are some control characters at the end of the two source files.
I removed them.

2.  A subroutine called ERROR is in the program.  This conflicts with a
system intrinsic.  I changed the name of the subroutine, but Lahey
technical support suggested declaring ERROR as EXTERNAL.

3.  Several subroutines have Hollerith data in DATA statements; the
variables are not declared as CHARACTER, but are declared REAL*8.  LF90
doesn't like this construct.  It was a simple change in most subroutines
to just declare the variable as CHARACTER*8.  A couple of the subroutines
shared variable names as both REAL*8 and CHARACTER.  These were a bit
more complicated as the name of the variable had to be changed.  It was
somewhat tedious to search out all the occurrences.

4.  A runtime error occurs on the DFLOAT intrinsic.  I changed this to
REAL at Lahey's recommendation.  It seemed to work OK.

5.  Lahey technical support recommended that all the xHaaa statements be
changed to 'aaa'.  I didn't find this necessary as the compiler only gave
warnings. 

6.  Lahey technical support also suggested that the new Fortran95 compiler
was more forgiving on Hollerith and offered to compile the source code
under their soon to be released LF95 compiler.  It compiled relatively easy
and they furnished the .EXE file for me to test.

I am up and running and have made the changes I needed to make to consider
geometric nonlinearity in Boundary Elements.