Summary Brief for:

1
X-CraftTechnology Overview
Captain David Comis ONR Code 33B Jim Webster
ONR Code 33/NAVSEA O5H1

• Summary Brief for
• USNA
• 22 April 2003

2
X-Craft Summary

• Purpose
• Experimental platform evaluating the hydrodynamic
  performance, structural behavior and propulsion
  system efficiency of high speed hull form
  technologies
• Evaluate mission modularity
• Science Technology
• Hydrodynamic experimentation (experimental data
  suite)
• Measure fluid flow, motions, dynamic loads,
  stresses, and speed/power requirements
• Lifting Body
• Designed to accept underwater lifting body(s) for
  hydrodynamic experimentation
• Drag Reduction
• Advanced polymer active drag reduction system
  installed on lifting body

3
Technology Insertion

• Lifting Body
• Fluid Drag Reduction/Polymers
• Modular Payloads in Mission Bay
• Modular payloads integrated into C4I
• UAVs/USVs/UUVs Capability
• Reduced Manning/Automation
• CODOG - Gas Turbines/Diesels/Waterjets

4
X-Craft Characteristics

• Length/Beam 73 m / 22 m (approx)
• FLD 1100 LT (approx)
• Propulsion (2) Gas Turbine Engines
• (2) Propulsion Diesels (CODOG)
• Propulsor (4) Waterjets (steerable/reversible)
• Speed 50 knots in calm seas in Combat Loading
  Condition
• 40 knots in Sea State 4
• Range 4000 NM/trans-oceanic range _at_ 20 knots
• C4I (2) COTS surface search radars LAN HF,
  VHF, UHF radios
• Survivability Operational through S/S 4
  survivable through S/S 6
• Mission Bay Support mission packages in ISO
  20x8x8 containers
• - multi-purpose stern ramp (launch/recover up
  to 11m RHIBs)
• - side RO/RO ramp (support fully loaded HMMWV)
• Flight Deck Landing spots for (2) SH-60Rs
  (day/night VFR)
• No maintenance facilities
• Crew 25
• Initial Sea Trials June 2004

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Combat Load Loading Conditions
X-Craft shall achieve speeds of 50 knots (125F
ambient, 104F seawater temp) in the Primary
Combat Loading Condition.

• Primary Combat Load Loading Condition is the
  Light Ship Loading Condition plus 150 tons of
  payload and adequate fuel and stores to operate
  for 5 hours at 50 knots and 5 days at loiter
  speed (12 knots)
• Secondary Combat Load Loading Condition is the
  Light Ship Loading Condition with 150 tons of
  payload and adequate fuel and stores required to
  perform the following mission
• Transit 800 NM _at_ 20 knots
• Operate 4 hours at 50 knots
• Operate on station at loiter speed (12 knots) for
  21 days
• Transit 800 NM back to port _at_ 20 knots

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Project Overview

• What we are trying to do
• High Speed Technology
• Develop
• Demonstrate
• Transition
• Environment
• Open Ocean
• Littoral

• What are we doing about it
• Getting close empirically
• MDO
• Parametric Models
• Reduce Risk Along the way
• Full Scale Trials
• Graduated Certification

• What we intend to learn
• Loads
• Structures
• Ship Motions
• Ship resistance
• Ship Propulsion

• What is different
• Dynamic Behavior
• Loads
• Temperature
• OPTEMPO
• Certification

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Transition of ST to Next Navy

• Science Technology
• Hydrodynamic experimentation
• Fluid flow
• Motions
• Dynamic Loads
• Speed/power requirements
• Structural Experimentation
• Primary stresses
• Secondary stresses
• Unsteady excitation
• Lifting Body
• Designed to accept underwater lifting body(s) for
  hydrodynamic experimentation
• Drag Reduction
• Advanced polymer active drag reduction system
  installed on lifting body
• Design Relevance Stochastically Enabled by
• Sub-Scale Physical Model Tests
• Finite Element Modeling
• Hydronumeric Modeling

8
Craft Performance Requirements(Objective
Functions)

• Evaluate high speed technology needed to achieve
• 20-Knot Open Ocean transit
• 40 Knots Sea State 4 Open Ocean
• Survive Open Ocean Sea State 6
• 50 Knots
• Conduct Operations in Theater 125 degrees F

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Design Getting the Right Craft

• Demonstrate High Speed Technologies Needed for
  LCS
• Materials
• Processes
• Certification ,Classification, Flagging
• Hydrodynamics for High Speed
• Lifting body test platform
• Drag Reduction test platform
• Stern Ramp Launch and Recovery
• Mission Modularity
• Multi-Objective Optimization
• Max Speed
• Endurance range
• Lightship Displacement

10
Resistance
11
Delivering Power in High Ambient Conditions

• LM2500 Gas Turbine (2)
• MTU 16V595TE92 (2)
• Kamewa 125SII (4)

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Propulsion
13
Weight reduction versus intended service

• Regulatory body structural design guidelines
• DNV Open Ocean operation is restricted for high
  speed craft
• Time from sheltered waters
• Minimal high loadings assumed
• No consideration for fatigue
• No consideration for extreme loads relative to
  special material properties relationship
  between yield and ultimate
• Heat treated materials
• Materials not lending themselves to
  non-destructive test inspection
• ABS Current rules are similar to DNV
• Direct Loads Analysis

14
Open Ocean Environment

• Wet deck impacts are critical loading condition
  for design accelerations
• Important factors to consider during design
• Clearance between mean waterline and wet deck
• Sea state
• Amplitude
• Period
• Ship Dynamic Response

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Environment

• Regulatory body guidelines
• Linear behavior (small amplitude responses)
• Implicit - seaway restrictions
• Restricted water operation reflects the
  peakedness and bandedness of benign
  environments
• Open ocean-greater spreading of amplitudes and
  periods
• Littoral environments wave energy concentrated
  close to ship dynamics resonant conditions
• Achieving reliability in structural design and
  ship stability
• design process consider probability of occurrence
  of overmatching events in the specified
  environment

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Performance - Ship Safety
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Ship Motions - Crew Safety

• Consequence
• Cognitive Degradation
• Physio-cognitive degradation
• Injury
• Mission Failure
• Death

• Process Variance
• Hydrodynamics
• No computational methods
• Sub-Scale Test Facilities do not support high
  speed following seas
• Risk Based Stochastic Methods can be used in lieu
  of non-existent dynamic stability criteria
• Viscous excitation

• Mitigation
• Sub Scale Tests to evaluate Failure Behaviors
• Sub Scale Tests Defining Incepting Events
• Neural Net Model Development to evaluate
  operational envelope
• Ride Control System Development

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High Speed Craft Motions
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Dynamic Stability

• Consequence
• Mission Failure due to Reduced Operability
• Capsize
• Certification for Intended Service

• Process Variance
• Hydrodynamics
• No computational methods
• Sub-Scale Test Facilities Limitations
• Risk Based Stochastic Methods can be used in lieu
  of non-existent dynamic stability criteria
• Dependence on Active Ride Control System - (Crew
  Comfort Obj. Funct.)
• Regulatory Body Rules
• High Level
• No prescriptive methods or metrics

• Mitigation
• Sub Scale Tests to evaluate Failure Behaviors
• Sub Scale Tests Defining Incepting Events
• Control Algorithm Development
• Evaluate operational envelope
• Feed into Ride Control System Development
• Transition Process, Methods and Metrics

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T-Foils
21
Interceptors - Design
22
Interceptors - Actuation
23
Trim Tabs
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Dynamic Loads

• Consequence
• High Accelerations
• High Pressures
• Structural Failure
• Mission Restriction
• Loss of Ship
• Reduced Ship Life due to Fatigue
• Reduced Operability

• Process Variance
• Hydrodynamics
• No computational methods
• Sub-Scale Test Facilities do not support high
  speed following seas
• Direct Loads Analysis Design Approach In Place -
  Needs Updating
• Structural Response Leading to Failure Partially
  Understood

• Mitigation
• Sub Scale Tests to evaluate extreme events -
  (slamming)
• Sub Scale Tests using Scaled Hydrodynamic and
  Structural Model
• Development of a Structural Operational Envelope
• Input to Ride Control System
• At sea graduated validation of ARCS

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System Performance Metrics for Ship Structures

• Structural Operational Capability (Co)
• the probability that the structure will support
  operational needs such as those associated with
  resisting combat, environmental or accidental
  loading.
• Structural Operational Dependability (Do)
• the probability that the ship structure will be
  there throughout the mission, once the mission
  begins.
• Structural Operational Durability (Ao)
• the probability that the ship does not need
  repair over its design life.

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Dynamic Loads Structural DesignTechnology
Development Areas

• Load and Load Effects
• Code development and validation
• SPECTRA, LAMP
• Probabilistic uncertainty characterization of
  modeling and basic variables
• Strength and Fatigue
• Analytical and numerical prediction methods
• Global lightweight structural strength
• Grillage strength
• Probabilistic fatigue
• Probabilistic uncertainty characterization of
  modeling and basic variables
• Criteria Development
• Reliability-based design approach addressing
  metrics(Co,Do,Ao)
• Serviceability Limit States (fatigue,
  deformation, stiffness)
• Strength Limit States (collapse, buckling,
  yielding)
• Reliability prediction methods per failure mode
• Reliability-based Acceptability Levels

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Speed - Power

• Consequence
• Equipment degradation
• Pump rotor erosion from cavitation
• Diesel loading at high torque conditions
• Excessively restricted operability
• Poor Acceleration
• Rapid degradation of performance over range of
  ship loading conditions

• Process Variance
• Hydrodynamics - Hull Form
• Model tests uncertainty (hull interference drag
  over range of speeds)
• Lifting Body Interference Drag not quantified
• Hydrodynamics - Propulsor
• Highly constrained design space
• Rotor
• Inlet
• Discharge

• Mitigation
• Potential flow numeric modeling of X-Craft with
  and without lifting body
• Viscous numeric modeling of steady flow into
  waterjet inlet
• Sub Scale Effective Power Tests
• Match to vendor waterjet data
• Full Scale Trials to determine CA

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X-Craft Waterjet Performance
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Maneuverability

• Consequence
• Poor Controllability at High Speeds
• Ride control system robustness
• Ride control system efficacy as stability
  controller during steady high speed maneuvers
• Excessively restricted operability

RCS
Appnds

• Process Variance
• Hydrodynamics
• No computational methods to predict excitation
  and restoration forces
• Control Surfaces operating at Speeds Where
  Supercavitation is expected
• High Aggregate Uncertainty
• Lifting Body
• No data at these high Reynolds Numbers

• Mitigation
• Sub Scale Tests to evaluate extreme events
• Sub-scale tests of appendages
• control surfaces
• lifting body
• Neural Net Model Development of excitation and
  response algorithms
• Migrate to Ride Control System Development

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Lightweight Materials (6061-T6 Aluminum)

• Consequence
• Structural Failure
• Mission Restriction
• Loss of Ship
• Reduced Ship Life due to Fatigue
• Reduced Operability

• Mitigation
• Design Review - Ensure all Requirements are
  understood
• Ship yard process review
• Welder Certification
• Coupon Testing
• Feed back delivered strength into FEA
• Refine Operational Envelope
• Codify into ABS rules - DLA process

• Process Variance
• Welding heat treated aircraft grade material -
  History of returning to fully annealed properties
  (8 vice 21ksi)
• Shipyard process
• Regulatory body (ABS) Certification
• Repair yard
• Deployed repairs
• Annealing conditions

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Science Objectives

• Resistance
• Fluid flow velocity measurements below free
  surface
• Free surface elevation measurements
• Pressure measurements
• Propulsion
• Laser measurements at ITTC stations
• Laser survey of waterjet rotor
• Flow Visualization
• Static Pressure measurements inside propulsor at
  ITTC stations
• Structures
• Accelerometers on submerged structure (TBL)
• Accelerometers to measure ship motions
• Pressure measurements for hull slams
• Strain Gages on primary structures
• Ring Laser Gyro to measure ship motions
• All relatively low risk but dependent on
  sub-scale data for statistical relevance

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Ship Flow Measurements

• Below Free Surface
• LDV along side of ship (velocity and turbulence
  data)
• Pressure Gages Along length of ship (static and
  dynamic pressures steady and in a seaway)
• Accelerometers along length of ship (turbulence)
• Above Free Surface
• Forward Looking Radar (Developmental)
• Wave Buoys
• Free Surface Topology Sensors

Surface Topology Measurements
LDV Apertures
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Waterjet Flow Measurements

• Flow
• LDV at ITTC 96 Stations 3 7
• LDV at lower lip of waterjet inlet
• LDV at upper surface of waterjet inlet
• LDV on Rotor
• Pressure
• Static Pressure Measurements
• All LDV Stations
• No Pitot tube rake
• Accelerometers
• On pump casing

Flow, Pressure, and Accelerometer Measurements
34
Modular Payload

• Total Open Systems Architecture Team (TOSA)
  developed modular payload interface and handling
  system
• Evaluated existing systems

35
Modular Payload Demonstration
36
Launch and Recovery

• NSWCCD CCD Developed System
• 11m RHIB
• 40 Specwar Craft
• Loads
• Assumed Relative Motions
• Applied to weight of fully loaded craft
• Recoverability
• X-Craft motions minimum at higher ship speeds
• Ability of craft to operate in wake at high speed
  unknown
• Low speed recoverability can be determined from
  sub scale test results

37
Launch Recovery Problem

• How do we safely recover manned unmanned
  vehicles at high speeds?
• Hydrodynamic problem
• 2 bodies with independent motions in fluid
  environment
• Overcoming vessel wake and propeller/waterjet
  turbulence
• Systems Engineering problem
• Expand operating envelope through intelligent
  Stern Ramp controls
• Launch Recovery system requirements
• Compact
• Robust
• Light-weight
• Low maintenance
• Capable of rapid deployment and stowage
• Modeling problem
• - Developing effective high speed launch
  recovery model tests

38
Notional Recovery Method
NSWC Carderock Code 23 proposal
39
Wake Issues
HSV wake at medium speed
40
Wake Issues
SKJOLD high speed wake w/ 11 m RHIB
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X-CRAFT Lifting Body with polymer Drag
Reduction Lifting Body Design Pacific Marine
(U.S.) ? Drag Reduction System Cortana
Corporation ? At-Sea Testing

• Drag Reduction Technology Insertion
• Polymer Polyethylene Oxide (PEO)
• Natural oxide consisting primarily of fish mucin
• Biodegradable (20 in 50 days 100 in 9 months)
• 1000-3500 PPM at ejection point
• Reduction of Pollutant Emissions (entire vessel)
• Reduced propulsion load improves emissions by up
  to 40
• Reduced transit times improves emissions by up to
  15

• Lifting Body
• Hydrodynamic body providing dynamic buoyant
  lift in ahead speed condition
• Active Ride Control system integrated to mitigate
  ship motions

• Lifting Body Objectives
• Measure Lift/Drag ratio
• Identify impact to top speed
• Safe Operation at all operating conditions
• Improve low speed ship dynamics (vertical plane
  damping)
• Increase payload capacity at high speeds

• Active Drag Reduction Objectives
• Reduce lifting body viscous drag
• Reduce atmospheric pollutants from propulsion
  plant
• Demonstrate active drag reduction applications

42
Flag Authority for US Navy Ships

• Classification
• Certification
• INSURV
• WESURV
• OPTEVFOR
• IMO
• USCG

USN
Safe To Operate
To procure
Technical Warrant Holder
Owner
Flag
Contractor
To build
Flag
Flag
Designated Certification Agents
ABS
To Review
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Summary

• X-Craft Performance Deliberately Outside the
  Range of Commercial and Military Experience
• Significant Developmental Testing is Underway
• ONR Committed to Risk Reduction Efforts with
  NAVSEA Support to ensure safe operation at the
  intended level of service
• Successful Technology Transition depends on
• Coherent sub-scale testing
• Numeric modeling
• Full scale trials
• Graduated operational certification
• Operational envelope
• Capture of knowledge in deterministic rules and
  design methods
• X-Craft will deliver the technology