31 Dec 94
evaluated and developed by a team of responsible
prior to embarking on a full scale three-dimensional
engineers who must determine the level of analyses
NISA. The Cray-based software usage would then be
and consultation necessary to obtain any of the
reserved for those rare monumental projects. It is
desired objectives stated in the ETL. The ETL can-
recommended that a micro-based version of this
not provide guidance for all possibilities.
software be utilized for most applications.
(5) A critical deficiency in the ABAQUS analyti-
A-4. NISA Application Recommendations
cal package is the lack of graphic preprocessing and
postprocessing routines. Adequate preprocessing
would eliminate much of the input generation errors.
Currently, there is no interactive preprocessing capa-
bility. Further development of preprocessing and
(1) This work would not have progressed with-
postprocessing routines should match formats
out the aid of several WES personnel. These individ-
provided by some of the more common processing
uals, currently running ABAQUS problems on the
routines currently being used by designers.
CRAY, provided a significant amount of consultation.
This type of aid will likely be necessary should dis-
(6) For these analyses, input to the user subrou-
trict users begin to utilize this software and
tines required changing the FORTRAN code to pro-
vide heat flux information, creep and shrinkage
characteristics corresponding to appropriate element
(2) This evaluation was performed over a
sets. Although many engineers can decipher
lengthy period of time. The time period was much
FORTRAN code, many involved in the work may not
longer due to a start-stop approach employed for the
have produced any programs for years. This can be
study. Several problems were identified during this
time consuming and is a waste of effort in the design.
period that seem to be shortcomings of the current
A more appropriate means for entering data would be
NISA process. Admittedly, some of the problems
via batch files to the user subroutines as is currently
encountered were due to the protracted approach
permitted. UMAT is an extremely comprehensive
taken. A start-stop operation is rarely an efficient
subroutine that is the crux of the time-dependent
stress analysis. Subsequent to this study, the capabil-
ity for entering data to the user subroutine through a
(3) Accessing the CRAY computer provides a
batch file was implemented.
variety of problems. Remote access for field use of
ABAQUS at this time is not possible. because
(7) For Districts to utilize ABAQUS in order to
ABAQUS is currently site licensed for use at WES.
execute a NISA as part of the design process, and to
Districts preparing to embark on such a study will
achieve the stated objectives in the ETL, ABAQUS
find it necessary to utilize WES personnel at WES or
must be readily available to District designers. With-
perhaps negotiate a contract with the ABAQUS
out these labor saving additions, ABAQUS use by
owner (Hibbitt, Karlsson, and Sorenson Inc.) to allow
designers outside of WES may never develop.
the District access to ABAQUS via the WES Cray.
Our conclusion is, that while the CRAY may provide
(8) Wide usage by Districts will no doubt require
significant computing capability, the logistical prob-
sophisticated support services in the form of training
lems to off-site users may provide more problems
and user support. This service is best provided by
than solutions for off-site users.
WES. Program orientation is recommended in the
form of a periodic PROSPECT course on the use of
(4) There has been a tremendous amount of
the NISA/ABAQUS system. Secondly, a staff mem-
effort expended in developing NISA via ABAQUS
ber(s) must be available to service the ABAQUS
and the user subroutines. The logical next step is to
system and provide user support. User support may
develop desktop software packages that would be
range from troubleshooting user problems to working
beneficial to Districts with smaller projects requiring
as part of the design team.
finite element analysis or larger projects where
preliminary two-dimensional modeling is necessary