OnDeck Software

The OnDeck software is a non-linear time domain code, specifically optimised for the development of operational limits and the analysis of on-deck interface issues.

OnDeck incorporates detailed non-linear models of the helicopters, including accurate representations of the undercarriage and rotor system. The code can model wheel sliding and lift off, the interaction with multi-contact surfaces, undercarriage loads, lashing loads, rotor and wind loads as well as the effect of restraint systems like RAST, ASIST, Decklock and the MacTaggart Scott TRIGON system.

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MRH90D

OnDeck was initially developed by the Australian Defence Science and Technology Organisation (DSTO) in 1988. AVT has been primarily responsible for maintaining, developing and validating the software since 1997.

ARHHelicopter Models Developed

  • S70B-2 / MH60-R Seahawk
  • S70A Black Hawk
  • SK 50/50A Sea King
  • MRH90 / NFH90
  • ARH Tiger
  • Squirrel (ADF)
  • Lynx Mk90b
  • SH-2G Seasprite
  • CH-47 Chinook
  • S92
  • Bell 222
  • A109

Helicopter Modeling

  • 6 DOF fuselage rigid body with integrated multi-degree of freedom undercarriage models including drag links and multi-stage oleos
  • Non-linear oleo and tyre stiffness and damping models including hysteresis and polytropic effects.

Ship Motion Data Input

  • Tilt table
  • Sinusoidal 6 degree of freedom input
  • SHIPMO7 frequency domain data
  • FREDYN time domain ship motion data
  • Experimental data
  • IMU real time ship motion data (MHA System)

Tyre Contact Modelling

  • Dynamic contact patch element methodology to capture tyre adhesion and sliding
  • Contact modelling based on tyre sectional properties enabling up to 85 deg combined lateral and longitudinal contact between the tyre and contact surface
  • Multi surface tyre interaction enabling tyre interaction with ramps and other obstacles to be accurately modeled.

Friction Model

  • Modified friction ellipse concept with tunable longitudinal and lateral friction coefficients for brakes on/off conditions, wet/dry deck conditions and static and dynamic motion.

Restraint System Models

  • DeckLock / Harpoon with actuation model and limit load and gimble angle limit criteria.
  • RAST / RSD model with limit load criteria. Traversable.
  • ASIST model with limit load criteria. Traversable.
  • MacTaggart Scott TRIGON system. Standby mode functional. Traverse / Render modes almost complete.

Wind Loads Model

  • Lateral wind fuselage model only at this stage.
  • 2D drag drag model is under development.

Rotor Loads Model

  • Flapping blade element rotor model provides dynamic response characteristics as well as aerodynamic effects.
  • Furher Matlab testing and OnDeck verification is being conducted.

Lashing Models

  • Non-linear models for chains, nylons and mitigators.
  • Moving axle and drag link lashings modeled.
  • Lashing failure mode capable.

Limit Conditions

  • Wheel sliding.
  • Wheel lift off.
  • Lashing loads.
  • Airframe tie down point loads.
  • Ship tie down point loads.
  • Undercarriage component loads.
  • Airframe / undercarriage clearance.
  • Restraint system loads and or gimble limits.
  • Relative motion position and attitude limits.
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