Multiphysics needs in the naval marine industry John D ... arising from underwater explosions and the hydroelasticity of ships in seaways. FENET THEMATIC NETWORK ... THAFTS* Î RESPONSE

FENET THEMATIC NETWORKCOMPETITIVE AND SUSTAINABLE GROWTH(GROWTH) PROGRAMME

Industry Sector RTD Thematic Area Date Deliverable NrMarine and Offshore Multiphysics & Analysis Technology 13/11/01 N/A

Multiphysics needs in the naval marine industry

John D McVee & Dr A P Steer

QinetiQ Rosyth, Centre for Marine Technology, Dunfermline, United Kingdom

SummaryAn overview is given of possible multiphysics applications with reference to current QinetiQ research including that aimed at validated design and analysis capability for Trimaran warships. Examples are given of current capability with regard to the fluid structure interaction arising from underwater explosions and the hydroelasticity of ships in seaways.


QinetiQ TrimaranResearch

• Theoretical and experimental research- materials- hydrodynamics- structures- survivability- propulsion- signatures

• Aimed at validated numerical model design and analysis capability


Multi-physics in the creation of high quality components

• Semi-levitation of titanium-aluminium alloys

• Involves- free surface flow- heat transfer- melting/solidification- electromagnetic fields

ALL COUPLED

Courtesy University of Greenwich


Multi-physics in marine & offshore : welding in shipbuilding

Courtesy University of Greenwich


Multi-physics in marine and offshore:

fluid structure interaction

FNB TRANSATFNB TRANSATCourtesy University of Greenwich


Design Requirements and Flow Features• Range of flow features for CFD to

capture- Viscous flows- Inviscid wave flows- Time dependent flows

• Initial requirement for CFD is to capture viscous flow features- Resistance- Inflow conditions to propulsion- Ship/propeller interactions- Detailed flow characteristics- Lift and drag for manoeuvring

coefficients

© P&O Nedlloyd


Propeller flow

• CFD can predict viscous flow

• includes separation• at full - scale

Blade pressure


Fully Appended Ship


RV Triton


Design considerations• Materials

- steels, castings, fibre reinforced plastics• Welding

- simulation of full and partial penetrations• Initial deformations

- vary as to methods of construction• Loading

- strip theory hydroelasticity- bow (and stern) slamming


Design considerations• Ultimate strength

- undamaged and damaged- ship collision

• Fatigue life- rolling and corrosion tolerances

• Crack propagation- stress intensity factors


Design considerations• Seakeeping• Propulsion

- Ship resistance• Noise & vibration

- structural bourne acoustics• UNDEX shock & whipping• Air-blast• Signatures

- radar cross section- target echo strength


Finite element idealisation of RV Triton

•Length - 98m•Displacement - 1100 tonnes•D.O.F’s - 416000•Number of elements - 133625


Finite element idealisation of RV Triton -truncated shock model

Fluid mesh

Centreline view of truncated shock model


Exemplar of current capability

LOADS MAESTRO ADEQUACY PARAMETER

DSA

MSC/NASTRAN

THAFTS* RESPONSE PATRAN

SUBSTRUCTURE MSC/NASTRAN* Three dimensional Hydroelastic Analysis of Floating Travelling Structures


Aim• Model federation• Interactive data exchange• Integrated multi-physics modelling capability

- fluid- structure- acoustic- thermal

• Begin with fluid-structure interaction- CFD/CSM fully interactive solutions- ship slamming, green sea deck loads


Problem solving environment

• Model integration at multiple levels• Enables appropriate level of integration across many models• Takes account of

- strength of the interaction- state of the art in each field

• Commercial commodity software- iterative solution between software trials- cell based solution of coupled problems- e,g, PHYSICA

Documents

Multiphysics needs in the naval marine industry John D ... arising from underwater explosions and the hydroelasticity of ships in seaways. FENET THEMATIC NETWORK ... THAFTS* Î RESPONSE