www.maestromarine.com Overview of the MAESTRO System 1 MAESTRO 2010
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Overview of the MAESTRO System
1 MAESTRO 2010
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Historical Highlights
Early Stages of Development and Fielding Professor Owen Hughes conceived and developed MAESTRO Wrote and published (Wylie/SNAME) textbook Ship Structural Design 1982 – 1983 Began moving MAESTRO into user community
Initial Cycle of Distribution, 1983 – 1989
Navies: United States, The Netherlands, The United Kingdom Commercial design organizations
Middle Period of Distribution, 1990 - 1999
Navies – total of 16 including Canada, Australia, Germany Ship Classification Societies – American Bureau of Shipping, Lloyds Register,
Bureau Veritas, China Class, Croatian Register of Shipping Commercial User Base – expanded to 40-50 companies University Licenses – 20+ universities worldwide
Recent Highlights, 2000 - 2010
Continued distribution throughout commercial industry Established links with Professor Jeom Paik and ALPS limit states analyses Expanded to handle larger models, faster, with improved solvers
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What is MAESTRO?
Beam Coarse Mesh Full-Ship Detail Full-Ship
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Rationally-based Structural Design
“design directly and entirely based on structural theory and computer-based methods of structural analysis and optimization to achieve an optimum structure based on a designer-selected measure of merit.” “A true design process must be capable of accepting an objective, of actively moving towards it, and of achieving it to the fullest extent possible.”
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Main Capabilities
MAESTRO is a complete ship structural design system.
Global Design Analysis • Rapid Structural Modeling • Ship-based Loading • Finite Element Analysis • Structural Failure Evaluation • Structural Scantling
Optimization • Hull Girder Ultimate Strength • Natural Frequency • Corrosion
Local Design Analysis • Integrated Coarse Mesh/Fine
mesh Analysis • 3rd Party Import/Export • Automated Global BCs
3rd Party Data Exchange • Hydrodynamic Load Interface • Import/Export Nastran Data • Geometry Import
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Structural Modeling
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• Ship hull consists of a series of segments: cargo holds, compartments • FEMs are large and complex, and construction should be done in a carefully planned
levels and sequences • Modules are helpful as they are ideal high-level building blocks
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The MAESTRO “Module”
Modeling Components Reference/Opposite Ends
Section Spacing/Number
Endpoints
Frames, Girders, & Strakes
Stiffener Layout/Spacing
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Ship Hull Girder Properties
Basic Ship Structural Properties Hull girder properties, e.g.
Inertias, Cross-sectional Area, Neutral Axis, Section Modulus, etc., can be recovered from the model.
Longitudinal Effectiveness On/Off
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Ship Based Loading
Lightship mass distribution Structural weight Weight distribution
Hydrostatic Loads Still water Waves
Tank Loads External bending moment and
shear force Cargo Masses
Forces Moments
Accelerations (6 d.o.f.) Pressure Loads Mass/Inertia Based Loads Hydrodynamic Loads
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Ship-based Loading
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Finite Element Analysis
Obtain the stresses throughout the model for all defined load cases.
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Structural Failure Evaluation (Limit States)
Evaluation Types
MAESTRO
ALPS/ULSAP
ALPS/HULL
Evaluate the entire ship for all of the different possible failure modes for each load case.
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Structural Failure Evaluation (Limit States)
Limit State Analysis The formulation of MAESTRO’s limit states is covered in Ship Structural Analysis and
Design and Ultimate Limit State Design of Steel-Plated Structures
These constitute the theoretical manual for MAESTRO’s limit state
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Structural Failure Evaluation (Limit States)
Evaluation is automatic - all structural members are evaluated to the factors of safety chosen by the user
Different factors of safety can be specified for all “collapse” limit states and for all “serviceability” limit states, or specified on a limit state-by-limit state basis.
In addition to the strakes, frames, and girders which receive full evaluation... Additional panels, triangles, and additional beams receive limited evaluation
Struts and pillars are evaluated for Euler buckling
Evaluation Patches
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Structural Failure Evaluation (Limit States)
MAESTRO Adequacy Parameters ALPS/ULSAP Adequacy Parameters
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Structural Failure Evaluation (Limit States)
Automatic Evaluation Patch (Panel) Generation
A patch is a collection of elements with its boundary supported by bulkheads or beams.
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Structural Failure Evaluation (Limit States)
Collects plate and beam elements
Automatic (or Manual) Evaluation Patch Generation
Represents the stiffened panels and correct panel parameters
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Hull Girder Ultimate Strength
ALPS/HULL, 2D (available now)
ALPS/HULL, 3D (near term implementation)
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Optimization
Uses sequential linear programing (SLIP2)
Optimization eliminates any structural inadequacies
While achieving user-specified objectives Least Weight
Least Cost
Weighted combination
Rationally-based Design Process (Optimization) Iterates structure through design cycles to
revise scantlings
Re-runs the finite element analysis
Re-evaluates the structural adequacy of each member for all failure modes and load cases
Process continues unit the structure has converged to an optimum design that has no structural inadequacies
“SLIP2 is able to solve problems involving a large number of constraints of various types and in which the objective may be any user-specified non-linear function of the design variables.”
Co
st U
nit
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Cycles
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Rationally-based Structural Design
1 CONSTRUCTION OF THE FINITE ELEMENT MODEL
FINITE ELEMENT ANALYSIS Calculate Load Effect (Q)
LIMIT STATE ANALYSIS Calculate Limit Values of
Load Effects (QL)
OPTIMIZATION OBJECTIVE
DESIGN EVALUATION Constraints satisfied? Objectives achieved?
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SPECIFICATION OF LOADS, LOAD PARAMETERS, AND DESIGN WAVES
FORMULATE CONSTRAINTS
g1 g2 g3 Q QL
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Fine Mesh Analysis
Fully integrated fine mesh modeling and analysis capability. Ability to import FEMAP/NASTRAN detailed models.
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Fine Mesh Analysis
MAESTRO Embedded Analysis Integrated local models into the global model
through Rspline elements
Solve coarse mesh model and fine mesh models
MAESTRO Top-Down Analysis Multiple models in a region
(1) solve coarse mesh model, (2) impose coarse mesh model nodal displacements as boundary conditions, (3) solve fine mesh models
3rd Party Top-Down Analysis Export fine mesh models with boundary conditions
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Natural Frequency Analysis
Perform a natural frequency analysis with or without added mass
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Corrosion
Corrosion is defined as an additive property to the original structure
Associated via a Load Case
Net thickness is automatically used in FEA and Limit State Analysis
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3rd Party Data Exchange
Hydrodynamic Code Interface, such as PreCal, Wamit, VERES, Lamp, Mora, etc.
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3rd Party Data Exchange
Import/Export Nastran Data
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MAESTRO Benefits
Easy to create, modify, and maintain coarse mesh model
Ship based loading
Tanks
Hydrostatics
Hydrodynamic Interface
Structural Panel Evaluation Paradigm
Integrated & Switchable Structural Criteria
Coarse mesh / Fine mesh coexistence
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Contact US
DRS Defense Solutions, LLC
Advanced Marine Technology Center (AMTC)
Stevensville, MD 21666
Phone: 410-604-8006
Fax: 410-643-5370
Email: [email protected]
Web: www.maestromarine.com