last modified: 01-JUN-1978 | catalog | categories | new | search |

NESC0682 GNATS/MESH2/GPRINT

GNATS, Nonlinear Stress Analysis of 2-D and Axisymmetric Static Structure by Finite Elements Method

top ]
1. NAME OR DESIGNATION OF PROGRAM:  GNATS/MESH2/GPRINT
top ]
2. COMPUTERS
To submit a request, click below on the link of the version you wish to order. Only liaison officers are authorised to submit online requests. Rules for requesters are available here.
Program name Package id Status Status date
GNATS NESC0682/01 Tested 01-JUN-1978

Machines used:

Package ID Orig. computer Test computer
NESC0682/01 CDC 7600 CDC 7600
top ]
3. DESCRIPTION OF PROBLEM OR FUNCTION

GNATS  is  a  finite  element
computer program  designed for nonlinear analysis  of axisymmetric
and two-dimensional static structures.
top ]
4. METHOD OF SOLUTION

The  GNATS  program  is   based  on  a  total
Lagrangian description of the displaced equilibrium configuration.
The complete strain-displacement equations are used to include the
effects of large displacements and large strains.  Elastic-plastic
material behavior,  with either isotropic or  kinematic hardening,
may be selected.   All solution options included  in GNATS contain
an equilibrium  check which assures  that the  structure satisfies
equilibrium to a specified tolerance at each stage of loading.
top ]
5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

All  large  arrays
in  GNATS,  MESH2,  and  GPRINT  are  dynamically  dimensioned  to
minimize storage requirements.
top ]
6. TYPICAL RUNNING TIME

For GNATS, running time is highly dependent
on the problem to be analyzed.  Running times for MESH2 and GPRINT
are nominal.
top ]
7. UNUSUAL FEATURES OF THE PROGRAM

GNATS   is  designed   for   the
general  nonlinear analysis  of  two-dimensional structures.   The
MESH2 preprocessor enables the user to generate either a four node
or eight node quadrilateral element and compute several parameters
which  are useful  in  evaluating the  mesh.   Mesh generation  is
accomplished by simultaneously defining the boundary of the domain
in  two spaces:   the r-z  plane which  contains the  plane to  be
analyzed, and an  integer i-j plane which controls  the density of
the subdivisions.  The integer i-j mesh is then mapped onto the r-
z domain  using Laplace's  equation in  second-difference form  to
determine the  coordinates of interior  nodal points.   The GPRINT
postprocessor  provides  users with  considerable  flexibility  in
selecting  the most  appropriate  data  to be  printed.   Variable
FORMAT statements provide additional printing flexibility.
top ]
8. RELATED AND AUXILIARY PROGRAMS

MESH2   was   developed    as   a
preprocessor mesh generator  for GNATS; GPRINT as  a postprocessor
output  editor.  VIEW  is  a graphic  display  program for  finite
element code  output data.  MESH2 and  GPRINT are supplied  in the
GNATS package; VIEW is not yet available.
top ]
9. STATUS
Package ID Status date Status
NESC0682/01 01-JUN-1978 Tested at NEADB
top ]
10. REFERENCES

M. L.  Callabresi and R. C.  Young, GNATS -  A Finite
Element Computer  Program for  the General  Nonlinear Analysis  of
Two-dimensional Structures, SLL-74-0023, October 1974.
             M. L.  Callabresi and  R. C.  Young, Organization  of
GNATS - A  General Nonlinear  Analysis Computer  Program for  Two-
dimensional Structures, SLL-74-0022, October 1974.
top ]
11. MACHINE REQUIREMENTS

Approximately 54,000  (octal) words  of SCM
plus a  problem-dependent amount  of ECS  is used  normally.  Disk
storage can replace ECS if one subroutine is changed.
top ]
12. PROGRAMMING LANGUAGE(S) USED
Package ID Computer language
NESC0682/01 FORTRAN+ASSEMBLER
top ]
13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:   SCOPE 3.4.
top ]
14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

  Some
plotting and system-dependent utility subroutines must be supplied
by the user,  as noted in comments  at the beginning of  each main
program.  Some  parallel coding must  be removed from  the COMPASS
subroutines, depending on whether the FTN or the RUN compiler will
be used.  MESH2, GNATS, and GPRINT were compiled by NESC, but they
were not executed because of the missing subroutines.
top ]
15. NAME AND ESTABLISHMENT OF AUTHORS

                 M. L. Callabresi and R. C. Young
                 Sandia Laboratories
                 P. O. Box 969
                 Livermore, California  94550
top ]
16. MATERIAL AVAILABLE
NESC0682/01
File name File description Records
NESC0682_01.001 INFORMATION 10
NESC0682_01.002 MESH2 SOURCE PROGRAM (F4) 1276
NESC0682_01.003 GNATS SOURCE PROGRAM (F4) 7741
NESC0682_01.004 GPRINT SOURCE PROGRAM (F4) 1821
NESC0682_01.005 AUXILIARY ROUTINES (COMPASS) 279
NESC0682_01.006 AUXILIARY ROUTINES (F4 + COMPASS) 212
NESC0682_01.007 MESH2 - SAMPLE PROB. INPUT DATA (CASE1) 9
NESC0682_01.008 MESH2 - SAMPLE PROB. PRINTED OUTPUT(CASE1) 97
NESC0682_01.009 MESH2 - SAMPLE PROB. INPUT DATA (CASE2) 25
NESC0682_01.010 MESH2 - SAMPLE PROB. PRINTED OUTPUT(CASE2) 1210
NESC0682_01.011 GNATS - SAMPLE PROB. INPUT DATA (CASE1) 12
NESC0682_01.012 GNATS - SAMPLE PROB. PRINTED OUTPUT(CASE1) 2729
NESC0682_01.013 GNATS - SAMPLE PROB. INPUT DATA (CASE2) 15
NESC0682_01.014 GNATS - SAMPLE PROB. PRINTED OUTPUT(CASE2) 873
NESC0682_01.015 GPRINT - SAMPLE PROB. INPUT DATA (CASE1) 4
NESC0682_01.016 GPRINT - SAMPLE PROB. PRINTED OUTPUT(CASE1) 466
NESC0682_01.017 GPRINT - SAMPLE PROB. INPUT DATA (CASE2) 7
NESC0682_01.018 GPRINT - SAMPLE PROB. PRINTED OUTPUT(CASE2) 301
top ]
17. CATEGORIES
  • I. Deformation and Stress Distributions, Structural Analysis and Engineering Design Studies

Keywords: difference equations, finite element method, mesh generation, nonlinear problems, two-dimensional.