| MAESTRO
can be used to analyze and design many types of thin-wall stiffened
structures, and has been used for virtually every type of ship from
large tankers, container ships and bulk carriers to high speed ferries,
multi-hull vessels, and SWATHs, as well as smaller vessels such as
fishing vessels and patrol craft. MAESTRO’s modeling and analysis
capabilities are not geometrically limited in any sense so that any
type of geometry or structural configuration can be accommodated by
MAESTRO.
MAESTRO’s
basic capabilities fall into four categories. The first is rapid
structural modeling. The MAESTRO Modeler is an interactive graphics
tool that allows a rapid creation of a full ship or other structure
finite element model, typically in days rather than weeks or months.
This model is used for finite element analysis, failure evaluation,
and structural optimization.
The
second major capability of MAESTRO is finite element analysis. This
is usually applied to the complete structure, and deflections and
stresses are determined for all principle structural members and
for all load cases. MAESTRO offers a ship-oriented, flexible and
highly automated specification of loads which are realistically
applied by MAESTRO to the structural model.
The
next major capability of MAESTRO is the failure analysis, where
each of the principal structural members are evaluated subsequent
to the finite element analysis for all possible failure modes. The
principal structural members of the global MAESTRO model typically
includes all of the stiffened panels and their associated beams,
transverse frame segments and longitudinal girders. These failure
modes address yielding, buckling, plastic hinge formation, and other
major failure modes and design limits such as deflections. There
are a total of 25 failure modes at the individual principal structural
member level, and 10 at the overall or multi-member level. The failure
analysis provides a quantified evaluation of each of these failure
modes for each principal structural member, for each load case that
is being analyzed. This is the most powerful such failure evaluation
capability available to the ship structural engineer, and results
in a high level of information that identifies structural problems
associated with events such as buckling. These structural failure
evaluations are used by the structural engineer to assess the adequacy
or degree of conservatism that is represented by the design, and
are also used by MAESTRO as constraints for the structural optimization.
The
next major capability of MAESTRO is its structural optimization,
which is based on a designer-specified optimization objective of
least weight, lowest vertical center of gravity, least cost, or
any weighted combination of these. MAESTRO interactively revises
the structural design at the level of the principal member scantlings
to achieve the optimum solution. The optimized design provides the
required safety margins against all of the structural failure modes.
These safety margins are controlled and specified by the user.
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further capability of MAESTRO is the translation of the global finite
element model to other formats, such as translation of the structural
model into a NASTRAN model.
The core MAESTRO capabilities that have been described are further
complemented by the ability to conduct detailed stress analysis
in local regions of the ship structure. The detailed stress analysis
module of MAESTRO consists of fine mesh modeling and stress analysis
of any portion of the structure, using a library of 24 finite element
types. This allows the modeling of complex detail such as corrugated
plating, openings and brackets, as well as modeling and analysis
of structure that is not incorporated into the global model. The
fine mesh model can remain within the global model as a statically
condensed superelement, which avoids the time consuming and error
prone process of transferring boundary condition data from a global
model to a fine mesh model. The detailed meshes are easily and rapidly
generated using MAESTRO’s powerful interactive graphics tools.
MAESTRO’s
output consists of graphics associated with the structural models,
displacements and stress data associated with finite element analysis,
structural evaluation adequacy parameters which are quantified evaluations
of each of the 35 limit state evaluations conducted by MAESTRO,
as well as deformation and stress data associated with the detailed
stress analysis module. All of this data is available both graphically
and in tabular formats. The MAESTRO graphics system allows immediate
user access to all of this data, and full flexibility for searching
against various criteria for stress and failure evaluation data.
MAESTRO
uniquely combines rapid structural modeling, ship oriented finite
element analysis, limit state or failure mode evaluations and structural
optimization in a highly integrated form that represents a unique,
efficient and powerful system for designing ship structures.
MAESTRO
is intended to introduce structural analysis, failure evaluation,
and optimization into the ship design process at much earlier stages
than finite element analysis has routinely been used. The structural
model and MAESTRO’s global, as well as detailed stress analysis
capabilities, can then support each phase of design through final
design and even then into detail level design. MAESTRO is also being
used extensively for repair design, as well as life-cycle structural
maintenance.
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