automated multidisciplinary design optimization method for multi-hull vessels kay gemba...
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Automated Multidisciplinary Design Optimization Method for Multi-hull Vessels
College of Engineering
Agenda
•Motivation & Introduction•Concept and Methodology•Models
▫Catamaran Synthesis Design Model▫Cost Model▫Seakeeping Model▫Model Integration and Variables
•Results•Acknowledgements
Motivation & Introduction
•Mono hulls can not archive high speeds needed for commercial and military application
•Multi-hull form vessels offer favorable characteristics▫Superior motion▫Improved seakeeping in rough weather
•Apply MDO method to preliminary design stage of a catamaran vessel concept
Concept and Methodology
Schematic description of the synthesis level MDO process
CAT-SDM
Cat. Synthesis Design Model
Synthesis Design Model
Model developedby CSC AdvancedMarine
Cost Model (SPAR Software)
•Estimate is based upon the hull’s structural components and the ship systems (piping, electrical, etc)
•Insurance•Risk analysis for Construction (cost risk
for labor and material), Re-work and Shipyard experience
Seakeeping Model•40 Neural Networks trained
for a specific heading angle and for a specific output:▫pitch, roll, bending moment,
shear force….• Inputs are length, spacing,
sea state and Froude number
•Result: Seakeeping Composite Index
Variables
Design Variables Design Constraints Design Objectives
Length on Waterline
Power (Boost Speed) Deadweight to Displacement Ratio
Beam Overall Beam Displacement to Resistance Boost
Draft Difference in Balance Cost
Depth Feasibility Checks
Block Coefficient Seakeeping
Model Integration and Workflow
iSight-FD
The Big Picture•Integrate modules into a workflow
•Define objective functions, constrains and inputs
•For each objective function run single objective MIGA to obtain feasible points spanning entire design space
•Utilize results from single optimization as initial population and optimize with multi-objective NCGA
•Result: pareto optimal solution
ResultsPreliminary results with Seakeeping
Iterations: Iterations:
Resources• Schmitz A. "Constructive Neural Networks for
Function Approximation and their Application to CFD Shape Optimization". Diss. Claremont Graduate University and California State University, Long Beach, 2007
• SIMULIA Engineous Software, iSIGHT-FD. 05 February 2009 <http://www.engineous. com/iSIGHTFD.cfm>
• Hefazi H. and Henriksen., "Automated Multidisciplinary Design Optimization Method for Multi-hull Vessels." CCDoTT Report, February 2008. Available on-line at www.ccdott.org.
Questions
Paper and Presentation availableat http://kai.gemba.org