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Review of existing numerical methods and validation procedure available for bird strike modelling 14th ICCES Conference, Jan 3-8 2007, Miami, USA

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Title: Review of existing numerical methods and validation procedure available for bird strike modelling 14th ICCES Conference, Jan 3-8 2007, Miami, USA


1
Review of existing numerical methods and
validation procedure available for bird strike
modelling 14th ICCES Conference, Jan 3-8 2007,
Miami, USA
  • Marie-Anne Lavoie
  • Augustin Gakwaya
  • - Laval University
  • David G. Zimcik
  • M. Nejad Ensan
  • NRC-IAR

2
INTRODUCTION
  • During the certification process, an aircraft
    must demonstrate its ability to land safely after
    being struck by a bird
  • Past experience has been to demonstrate this
    compliance through full-scale test
  • Bird models are generally developed based on
    tests data that are nearly 30 years old
  • Aim to summarize the steps involved in creating a
    bird model

3
INTRODUCTION
  • THEORY of bird strikes and an analytical
    evaluation of the expected results
  • EXPERIMENTAL DATA that are currently available
  • Description of the three NUMERICAL BIRD MODELS
    one can use
  • Analysis of the RESULTS
  • Recommendations are made in the CONCLUSION
    regarding the best suitable method

4
THEORY
  • High velocity bird impact Þ hydrodynamic behavior
  • Event is divided into two stages
  • Shock Hugoniot pressure
  • Steady flow Stagnation pressure
  • Equation of state

5
EXPERIMENTAL DATA
  • Most complete results Wilbeck (1977)
  • Gelatin with 10 porosity
  • Density of 950 kg/m3
  • Shape of projectile

6
EXPERIMENTAL DATA
7
EXPERIMENTAL DATA
Normalized Hugoniot Pressure Normalized Hugoniot Pressure
Experimental Analytical
116 m/s 3.5 14.9
197 m/s 7.8 12.0
253 m/s 3.4 10.5
8
EXPERIMENTAL DATA
  • Current work in bird testing
  • Best practice tends to tweak numerical model to
    fit test data from impacted aeronautical
    structures
  • Down side of this general approach is that bird
    models are specific to their application
  • Industries which have financed recent bird strike
    tests are not willing to make their knowledge
    public.

9
NUMERICAL BIRD MODELS
  • Early stages of bird impact simulations, the bird
    was represented by a pressure pulse on the
    structure.
  • Three main modelling methods are currently
    available. They are
  • the Lagrangian mesh
  • the arbitrary Lagrangian-Euler (ALE) mesh
  • the smooth particle hydrodynamics (SPH) method.
  • 1 kg bird travelling at 116 m/s impacts on a
    0.5?0.5 m rigid square plate.

10
NUMERICAL BIRD MODELS - Lagrangian
  • 500 hexahedral elements
  • Fluid-structure interaction controlled through
    contact between bird and target

11
NUMERICAL BIRD MODELS - ALE
  • 19,000 hexahedral elements of equal length, width
    and height
  • Fluid-structure interaction controlled through
    constrained Lagrange in solid

12
NUMERICAL BIRD MODELS - SPH
  • 4600 SPH particles each weighing 0.224 gr (0.0005
    lbs)
  • Fluid-structure interaction controlled through a
    node-to-surface contact between the bird and
    the target

13
RESULTS - Lagrangian
14
RESULTS - Lagrangian
15
RESULTS - ALE
16
RESULTS - ALE
17
RESULTS - SPH
18
RESULTS - SPH
19
CONCLUSION
  • The comparison with the experimental data
    highlights the need for future bird calibration
    testing
  • The Lagrangian method is no longer suitable
  • ALE and SPH models compare well with the
    analytical predictions
  • Currently, the ALE method is a standard approach
    to bird impact modelling
  • The SPH method formulation works well and is
    still developing
  • We are working on an improved version of SPH
    method which will interact with a solid structure

20
ACKNOWLEGMENTS
  • Laval University
  • National Research Council of Canada (NRC)
  • Consortium for Research and Innovation in
    Aerospace in Quebec (CRIAQ)
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