the development of ditching and water impact design limits n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
THE DEVELOPMENT OF DITCHING and WATER IMPACT DESIGN LIMITS PowerPoint Presentation
Download Presentation
THE DEVELOPMENT OF DITCHING and WATER IMPACT DESIGN LIMITS

Loading in 2 Seconds...

play fullscreen
1 / 26

THE DEVELOPMENT OF DITCHING and WATER IMPACT DESIGN LIMITS - PowerPoint PPT Presentation


  • 105 Views
  • Uploaded on

THE DEVELOPMENT OF DITCHING and WATER IMPACT DESIGN LIMITS. PRESENTED AT INT’L CABIN SAFETY CONFERENCE NOVEMBER 17, 2004 LISBON, PORTUGAL DYNAMIC RESPONSE INC. (DRI) FEDERAL AVIATION ADMINISTRATION (FAA-TC). SBIR WATER IMPACT PROGRAM. PHASE I Feasibility of Hybrid and FEM Methodology

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'THE DEVELOPMENT OF DITCHING and WATER IMPACT DESIGN LIMITS' - vanida


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
the development of ditching and water impact design limits
THE DEVELOPMENT OF DITCHING and WATER IMPACT DESIGN LIMITS

PRESENTED AT INT’L CABIN SAFETY CONFERENCE

NOVEMBER 17, 2004

LISBON, PORTUGAL

DYNAMIC RESPONSE INC. (DRI)

FEDERAL AVIATION ADMINISTRATION

(FAA-TC)

sbir water impact program
SBIR WATER IMPACT PROGRAM

PHASE I

  • Feasibility of Hybrid and FEM Methodology

PHASE II

  • Perform Full Scale Tests, Model and Correlate (KRASH and MSC/DYTRAN)
  • KRASH Model For Existing Scale Model Ditching test
  • Evaluate FAR27/29 Water/impact/Ditching Regulations & Compliance
  • Develop Preliminary Water impact Design Limits With KRASH

PHASE III

  • Develop Military and Civil Helicopter KRASH Models
  • Evaluate Correlation Techniques/Procedures
  • Develop Design Criteria & Design Envelopes (DLE) & Procedures- Using KRASH

--- Ditching and Water Impact

--- Civil helicopters

--- Military helicopters

  • Recommend Ditching and Water Impact Design Criteria
significant questions
SIGNIFICANT QUESTIONS
  • Can modeling simulate /represent the significant aspects of full-scale impact and scale model ditching tests?
  • Can analytical modeling be an effective tool in the development of crash design criteria?
aspects of water impact and ditching
ASPECTS OF WATER IMPACT AND DITCHING
  • Kinematics Behavior
  • Overall response
  • Discrete location response
  • Failures
  • Design parameters
  • Seat-occupant performance/tolerance
  • Trends & relationships
full scale water impact tests
FULL SCALE WATER IMPACT TESTS

1998 - 1999 Tests of UH-1H

Test S1

26 fps vertical

Test S2

28 fps vertical

39 fps longitudinal

significant questions1
SIGNIFICANT QUESTIONS
  • Can modeling simulate /represent the significant aspects of full-scale impact and scale model ditching tests?
  • Can analytical modeling be an effective tool in the development of crash design criteria?
design considerations seat load limit
DESIGN CONSIDERATIONS-SEAT LOAD LIMIT

NO SEAT LOAD LIMIT

14.5G SEAT LOAD LIMIT

26 FPS VERTICAL WATER IMPACT

s2 s1 pressure trend comparison analysis vs test
S2/S1 Pressure Trend Comparison; Analysis Vs. Test

Resultant Velocity

S1 Test = 26 FPS

S2 Test = 48 FPS

S2/S1 Velocity Ratio 1.85

S2/S1 KE Ratio

3.41

trends
Correlation

Sea State Levels

S2/S1 Test Levels

Pressure

Acceleration

Transfer Function (Accel. to Pressure)

Filter Levels

Design Envelopes

Panel Failure

Floor Acceleration

Mass Item Response

Occupant-Seat Response

VS.

Panel Strength

Pitch Attitude

Seat Load Limit

Velocity Profile

Sea State

TRENDS
ditching compliance procedures
DITCHING COMPLIANCE PROCEDURES
  • Scale Model Testing

- rigid, deficient, misleading, costly

  • Similarity to Existing Designs

- questionable basis

  • Pressure Calculations

- static flotation analysis

  • Vertical Load Factor Calculations

- stall speed, no sink velocity

  • Procedures

- under-estimate pressure & acceleration

what exists relative to ditching assessment capability
What Exists – Relative to Ditching Assessment Capability
  • Inadequate evaluation and compliance procedures
  • KRASH modeling features that address significant issues, i.e. trends, sea state, nose-over, failures
  • Analysis predictable within a level of acceptance
  • Analysis simulation time efficient
applicability to far 25 transport category aircraft
APPLICABILITY TO FAR 25; TRANSPORT CATEGORY AIRCRAFT

FAR 25, FAR 27 and FAR 29 HAVE

MANY SIMILARITIES:

  • Ditching Envelope
  • Seat Dynamic Test Requirements
  • Mass Item Retention
  • Acceptance Criteria
  • Compliance Procedures
summary
SUMMARY
  • Balanced Test, Analysis, Design SBIR

- F/S WI and Scaled Ditching Tests

- Civil and Military Rotorcraft Models/Correlation

- FAR 27/29 and Military Design Specifications/Compliance

  • Development of Ditching Criteria and Design Limit Envelopes Based On;

- Occupant –Seat-Restraint System Integrity

- Structural and Mass Retention Integrity

- In Excess of 300 Simulations Performed

  • Applicability of DLE to Evaluate Design Strength, Operational Conditions, Acceptance Criteria, New Designs, FAR 25, 27, 29
  • End Product Goal- Recommended Ditching and WI Design Criteria, DLE and Procedures