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Why we
use SAGA
We have developed
our structural design procedures around SAGA to obtain a
reliable, repeatable, and cost-effective method to ensure our clients
receive consistent high quality work by our engineering departments. We
have achieved a flexible structural modeling, loading and evaluation tool
interacting with other efficient software such as FEMAP, Nastran, WADAM,
and Wasim.
The SAGA computer program has
been applied to ships and offshore structures made from
steel, aluminum, and composites construction materials.
Typically the task at hand is to design
the structure such that an agreed upon set of criteria such as classification
society codes are satisfied. SAGA saves our engineers a tremendeous amount
of tedious work related to ensuring a design is adequate and
optimal by allowing assessment against any number of rules and any number
of load cases into one plot showing maximum response for each structure under
design. We have obtained a method which allows the plotting of results into
typical structure groups to easily understand the results and allowing easy
access to the data needed to update structural drawings.
SAGA is developed strictly with this
purpose in mind and assists the user in keeping the structural assessment under
control during the design as well as when time comes to present the results.
The program is capable of presenting the results in either graphical and
spreadsheet form, and can be made to present results for all elements or simply
only the areas that require attention.
Main Features - SAGA Features
SAGA performs the code check calculations required for structural
classification of ships, and in addition we also create user-defined
calculations that can be imported into spreadsheets for further use. Results of
the program have been accepted by classification societies such as American
Bureau of Shipping, Bureau Veritas, and Lloyds Register of Shipping.
SAGA allows extraction of any data
typically contained in a finite element model and also allows introduction of
user-defined data items. The user can assign such data items to groups of the
model for analysis purposes.
SAGA imports finite element analysis
models from a variety of finite element packages including Nastran, Ansys,
Maestro, ABS SafeHull, BV VeriStar, and SACS. The geometry, materials,
properties, nodal displacements, and element stresses are imported and
available for further analysis by SAGA. The actual results from the finite
element models are also applied to the database and available for evaluation
against allowable values.
3-D Modeling
SAGA is used to
rapidly create ship finite element models via import of CAD transverse section
offset data in formats used by surface modeling tools. The
file formats supported include Autocad .dxf, GHS .gf1, and HECSALV .hul
files. The system supports
assembly of models created by several individuals using SAGA in combination
with a finite element modeler such as FEMAP, ABAQUS, or ANSYS. This
method supports parametric assessment of a number of structural configurations
under consideration. Local models can be made from the global model using
features like nodal section insertion and beam shapes-to-plate data
extraction. The local models are loaded by nodal deflections and
rotations as well as pressure loading.
Loading Analysis,
Balancing, and Interfaces to External Programs
The grouping of finite
elements is carried out by SAGA to support naval architecture loading groups
throughout the vessel. The loading
groups include the external hull, tanks, deck areas, engine room and other user
defined groups depending on the analysis requirements. The
hull group can be exported in Nastran format for loading by external programs
such as WASIM, WADAM, LAMP, or by SAGA using built-in classification society
rules. Upon the loads being added we use SAGA to either inertia balance or
position balance the model to eliminate boundary condition influcence.
Evaluation of Results
SAGA performs advanced
post-processing of results by establishment of structural failure regions in
combination with material, property, deflection, and stress data from the
finite element model. SAGA is
capable of using classification society rules from ABS, DNV, BV, Lloyds, and
user defined failure rules. The
failure rules are programmed by the user via spreadsheet interface.
Additional Features
The program is highly
flexible and customizable supporting the unique requirements of each vessel
being analyzed. The program
provides weight analysis of the entire vessel or user groups.
SAGA (Structural Assessment Graphical
Assessment) provides a fresh look at using structural finite element models for
a number of purposes from an early design stage to final design.
Viking Systems, Inc. also
assists clients with the creation and evaluation of structural finite element
models for any purposes.
Computer
Platform - PC Requirements
The program runs under the Microsoft Windows operating systems.
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