Bird strike Analysis on Aircraft structure using SPH Model · 2020. 7. 30. · Bird strike Analysis...
Transcript of Bird strike Analysis on Aircraft structure using SPH Model · 2020. 7. 30. · Bird strike Analysis...
Bird strike Analysis on Aircraft structure using SPH Model M.Dakshina Moorthy
1, T.Chakravarthi
2,
1Department of Mechanical Engineering, VANI1, chevutur
Email: [email protected] 21
Department of Mechanical Engineering, VANI1, chevutur
Email: mailto:[email protected]
Abstract: As a result of aerial vehicles collisions
with birds in the air, there are many accidents that
cause high cost and sometimes losing of life. In the
aviation sector, bird impact is considered an
important problem that causes material damage and
threatens flight safety. Bird-strikes on aircraft is a
major threat to human life and there is a need to
develop structures which have high resistance
towards these structures. It is imperative that today's
designed and manufactured aviation structures
comply with safe flight and landing requirements. In
order to satisfy these requirements, the behavior of
structural parts against bird impact is investigated.
In order to reduce the experimental costs, test is
studied on designing a leading edge by using the
finite element methods. In this study Smooth
Particle Hydrodynamics (SPH) and CEL (Coupled
Eulerian Lagrangian) was used for modeling the bird
Through the obtained results, it is aimed to improve
the design process and to produce more durable and
safe structures. But the high cost of testing and of
the "trial-and-error method" to increase the number
of tests, manufacturers are forced both time and
financially.
1.0 INTRODUCTION
Foreign material impact is a serious problem for
aircraft structures in general. Bird strike is one of
those, which causes significant loss of money and
human life. Because bird strike causes about 90%
percent of the aircraft accidents, people have been
trying to protect and strengthen aircrafts from bird
strike since early 1970s. Pilots may face from two to
five bird-strikes among their carrier since in-service
knowledge indicates that bird-strike occasions are
common incident in aviation. The first known bird
strike accident was recorded in 1908 in the Dayton /
Ohio / North Carolina region of the United States as
the murder of a bird by Orville Wright who is one of
the co-founders of the first plane which have a steam
engine. It can be given as an example of the accident
that there was no loss of life by forced landing in
Hudson River in New York city of United States of
America in January 2009, which was registered as
one of the biggest known accidents. The first bird
strike to a jet powered aircraft was in Germany in 27
August 1939. The first test flight of a jet powered
aircraft was on 24 August 1939. Three days later,
during the second flight, a loss of thrust was
experienced after a bird strike. Bird-strike events
postures significant threats to civilian and military
aircrafts as they lead to fatal to basic aircraft
components. Fuselage, engines, wings, windshield,
nose/radom are most common aircraft components
stricken by birds according to reports. Figure 1-1
shows those components of an aircraft that have a
risk of a bird-strike.
Fig. 1. Illustration of aircraft components
exposed to the risk of bird strike.
1.2 BIRD STRIKE PROBLEM
1.2.1 The Importance of Bird Strike in Aviation
As a result of the collision of an aircraft with foreign
objects, material and life-lost accidents occur. This
phenomenon, which is called as a foreign material
impact in the field of aviation, is examined in two
different sub-sections. One of these subsections,
solid body impact; a piece of metal that has fallen
from another aircraft or a stone which is on the
runway is often struck by the force of the wind on
the airstrip and hit by the aircraft. Another sub-title,
which is the subject of examination of this thesis at
the same time, is an accident that occurs when one
or more birds collide with aircrafts that may lead to
loss of human and bird life. The main difference
between these two collision states is that the solid
body reacts rigidly during the collision, while the
bird usually behaves in the direction of
fragmentation during bird collision. These two
behaviors have different effects on the structural
elements of the aerial vehicle. Bird strike is one of
the most important problems encountered in civilian
and military aviation areas. Guida (2008) stated that,
it is estimated that around 36,000 birds have been hit
every year worldwide. [12]
2 Literature Review
In this section, previous researches about bird strike
are carried out and necessary information related to
the subject of this research are given. Researches
about bird strikes has been started since 1970s and it
is still a current subject to work on.
Experimental equations are traditionally used to
analyze bird strike problems to determine the
thickness of structural components required to resist
bird strikes. However, the airworthiness
requirements have changed slightly and
experimental equations have not adequately met
today’s highly optimized complex aircraft
structures. Many researchers have focused on bird
strike research using computers and related
softwares in the last few decades.
Figure 2.1: Multi-material Bird Model
Airoldi and Cacchione (2006) evaluated the
numerical performances of bird models with
different material characterization and shapes using
Lagrangian approach. The approach has been
applied to analyse bird impacts in idealized
conditions considering the normal impact on a rigid
target. Lagrangian approach has been found suitable
to perform a large number of analyses focusing on
the impact loading parameters obtained by bird
models of different shapes and accepting different
material characterizations. [11]
In order to reduce the experimental costs, Guida
(2009) studied on designing a leading edge by using
the finite element methods. In this study Smooth
Particle Hydrodynamics (SPH) was used for
modeling the bird whereas a classical finite element
approach accepted. Greatly similar results between
the experimental test and the SPH bird numerical
model were obtained. Figure 3 shows the
comparison of the test and simulation. [13]
Figure 2.2: Numerical and Experimental Shape
after the Impact
Analyzing a novel rib-less tailplane of a C27J
aircraft is approved by an experimental bird-strike
test. Advanced numerical simulation techniques can
significantly help to design safer and more efficient
aircraft structures capable of withstanding a bird-
strike is shown by these results. [14] [15] [16]
Heimbs (2011) examined the effects of collisions at
high speeds on boom composite plots, along with
the phenomenon of bird hitting. Lagrangian and
Eulerian impactor models have been compared in
this study. [17] This comparision is given in Figure
4.
Figure 2.3: Bird strike simulation on composite
plate with the (a) Lagrangian and (b) Eulerian
impactor models
Ubels (2003) investigated several composite leading
edge designs for a bird strike and these designs are
based on a novel application of composite materials
with high energy-absorbing characteristics: the
tensor-skin concept. [18] Furthermore Reglero
(2010) examined bird impact events on aluminum
foam composite composite wing structures. [19]
Heimbs (2011) observed how composite leading
edge reacts to a bird strike using Abaqus/Explicit
finite element software. Bird strike on a rigid plate
analyses were performed firstly in order to validate
the bird model then this validated bird model was
used to analyse a bird strike on a composite wing
leading edge. It is appeared that final simulation
results correlate with the experimental data in this
study. [20]
3 SIMULATION OF BIRD STRIKE
3.1 Simulation Steps In this section, the steps for the analysis of a bird
strike that have to be followed is going to be
described. The analysis of bird strike can be divided
into four main parts. First, the problem should be
defined along with the aviation standards. In this
context, the impact location, bird shape and weight,
impact speed should be clearly assessed. Secondly,
the appropriate solution should be chosen. In
addition, required material model for the soft
impactor must be selected. Thirdly, material models
should be determined according to metallic and non-
metallic aircraft structures. Finally, the bird
simulation is going to be performed. Figure 3-1
shows the flowchart for suggested procedure of bird
strike analysis.
Figure 3-1: Flowchart for Bird Strike Analysis
Procedure
3.2 Problem Description and Modeling of Bird
Geometry
Dead bird or chicken corpses are used in the bird
strike certification tests. However, in the
experimental tests, various materials are used which
have specific geometric shapes reflecting a bird
body. Considering the variability of bird species and
the variations in the impact, the bird model must
have a certain degree of similarity to that used in
experimental tests.
Figure 3-2: Bird Strike Experiment Set-up
One of the most important parts of the bird impact
analysis is determining the appropriate bird model.
Model designation includes bird geometry and
material selection. There are certain geometric
shapes commonly used in bird geometry. These are
cylindrical, cylindrical hemispherical ends,
ellipsoidal and spherical shapes. In particular, the
cylindrical hemispherical ends and ellipsoidal
shaped bodies yielded closer results to the actual
bird body in the tests. Figure 3.2 shows the bird
model geometric shapes that Heimbs (2010)
indicated in his paper. [30]
Figure 3-3: Different Substitude Bird Impactor
Geometries
Federal Aviation Administration (FAA) have some
regulations for the bird strike test condition.
According to FAA’s Issue Paper G-1, bird strike test
condition is given by the parameters in Table 3-1.
Table 3-1: FAA Bird Strike Conditions
The bird strike requirement is specified as:
(a) The aircraft must be capable of continued safe
flight and landing during which likely structural
damage or system failure occurs as a result of –
(1) In airplane mode, impact with a 4-pound bird
when the velocity of the aircraft relative to the bird
along the aircraft’s flight path is equal to Vc at sea
level or 0.85Vc at 8,000 ft, whichever is more
critical;
(2) In VTOL/conversion mode, impact with a 2.2
pound bird at Vcon or VH (whichever is less) at
altitude up to 8,000ft.
(b) Compliance must be shown by tests or by
analysis based on tests carried out on sufficiently
representative structures of similar design.
where, VC is cruise speed and VH indicates the
hover speed.
3.3 Bird Model
The bird material has been replaced with an equal
mass of water, as birds mostly consists of water and
air trapped in the bones and lungs. The bird
geometry is represented as a cylinder with
hemispherical ends as this geometry resembles the
pressure time history of the real bird during the
impact tests as shown in Figure. The bird
characteristic such as diameter, cylinder length and
density are obtained by using empirical formulas.
A bird with mass equal to 2 pounds has been
considered in this analysis as per the certification
requirement.
Bird mass = 4 lb = 1.8 kg
Density = 960 kg/m3
Diameter = 0.077m
Total Length = Cylinder Length + Diameter =
0.225 m
Figure 3-4: Bird dimensions that is used in the
analysis
As birds, mostly composed of water, a water-like
hydrodynamic response has been considered as a
valid approximation for a constitutive model for bird
strike analyses. The Equation of state (EOS)
describes the pressure-volume relationship with
parameters of water at room temperature, hence the
Mie-Grüneisen EOS Us-Up approach in
Abaqus/Explicit was adopted for this purpose.
4. SOLUTION TECHNIQUES Selecting the method to be used in the analysis is
one of the most serious issues in the simulation of
the bird impact problem. In this section it will be
examined what the basic finite element solution
techniques used for non-rigid bodies during collision
simulation are. It will also show applicability to the
bird strike problem, taking into account the
advantages and disadvantages of the finite element
methods mentioned. There are basically four finite
element approaches that can be used in the
simulation of the bird impact problem. These
approaches are; Lagrangian Solution Technique,
Eulerian Solution Technique, Arbitrary
LagrangianEulerian Solution Technique (CEL) and
Smooth Particle Hydrodynamics Solution Technique
(SPH). The main difference between these
techniques is the solution networking approach.
4.1 CEL (Coupled Eulerian Lagrangian) Solution
Technique
In the classic Euler approach, the solution network
reflects a fixed area in space, and the area to be
computed should cover the area where the material
is likely to be found, except for the environment in
which the material is located. For this reason, the
classical Euler approach requires more computation
than the Lagrange approach. In addition, in order to
approach the same result with Lagrange approach,
solution network elements are needed in a smaller
structure. Given all these disadvantages of the
classical Euler method, the CEL method allows
much more efficient analysis.
Figure 4.1.0 : CEL Modeling Method for Soft
Body Projectile
In conclusion, the CEL approach allows for more
efficient fluid-solid body analysis by taking good
aspects of the Eulerian and Lagrangian approaches.
On the other hand, it is trying to get rid of the
disadvantages of Euler and Lagrange methods. The
disadvantage of the CEL method is that the user has
to be experienced while determining the solution
network volume. Figure 4.6 shows the element
deformation in CEL bird model.
mDiameter
DiameterDensity
MassBirdLengthCylinder 146.0]
6**[*4
2
Figure 4.1.2: Bird strike simulation on rigid
plate with CEL impactor model
4.2 SPH (Smoothed Particle Hydrodynamics)
Solution Technique
In addition to methods such as Lagrange, Euler and
ALE, SPH (Smooth Particules Hydrodynamics)
method has been developed in order to get rid of
solution network problems and to make more
efficient analyzes. Initially developed for the
calculations of astrophysical collisions at hypersonic
speeds in the 1970s, fluid-rigid interaction problems
from the beginning of the 1990s, collision
simulations, analyzes of fragile and bendable
structures, and analyzes subjected to high
deformation. The bird collision problem, which
occurs in large diameter deformation, is suitable for
use with the SPH method. [32]
Figure 4.2.0 SPH Modeling Method for Soft
Body Projectile
Fig.4.2.1 Finite element mesh and SPH particle
distribution
In addition to methods such as Lagrangian, Eulerian
and ALE, SPH (Smooth Particles Hydrodynamics)
method has been developed in order to get rid of
solution network problems and to make more
efficient analyzes. Initially developed for the
calculations of astrophysical collisions at hyper-
sonic speeds in the 1970s, fluid-rigid interaction
problems from the beginning of the 1990s, collision
simulations, analyzes of fragile and bendable
structures, and analyzes subjected to high
deformation. SPH method is suitable for use with
the bird strike problem with large deformation.
Thanks to the mesh-less structure of the SPH
method, there are no solution network problems
resulting from large deformations. The conventional
solid Lagrange solution significantly reduces the
step time in the elements, which are deformed
compared to the solution network and is fixed.
According to the Euler method, the SPH method
requires far fewer elements. It is also easy to follow
the deformation behavior of each particle as in the
Lagrange method. [22] [30] [33]
Figure 4.2.2: Bird strike simulation on rigid
plate with SPH impactor model
On the other hand, the SPH method also have some
disadvantages. There is a high memory and CPU
requirement for the calculation, and this problem is
inherited by parallel multiprocessor computers.
Another disadvantage is that, when the boundary
conditions are determined, the relative value of the
particles deviates from the true value when the
boundary conditions are exceeded.
4.3 Comparison of the Solution Teqniques
CEL and SPH finite element methods investigated
with advantages and disadvantages in this chapter
will be compared with one another in this section
and the method to be used within the scope of this
thesis will be selected. CEL and SPH methods give
more feasible results. On the other hand, in the SPH
method to be used as an analysis method in this
thesis study, birds will be expressed as particle and
rigid plate will be expressed according to Lagrange
solution network method. With the SPH method, the
greatest amount of deformations in the bird element
are represented most appropriately and the closest
results to the actual conditions are approached.
Heimbs (2010) made a table about advantages and
disadvantage about of bird modeling methods. [30]
Table 4.3: Comparision between CEL and SPH
Method
5. Bird-strike analysis
5.1 Bird geometry validation.
In order to validate the bird geometry which is going
to be used in this thesis, it is used in a bird strike
analysis on a flat plate, and compared the results
with an experimental test and a numerical solution
found in literature research.
The displacement vs. time , strain vs. time and
reaction force vs. time histories of the plate were
recorded, For each test group, two experiments were
conducted UNDER CEL MODEL AND SPH
MODEL and the experimental results showed good
repeatability. For all the tests conducted, no damage
or failure was observed on the plate.
5.1.1 Test 1:
Fig 01 displays the experimental results for test No.
1, The actual impact velocities are 60 m/s on both
SPH Bird Model and CEL Bird. These values are
very close to the expected impact velocity of 60 m/s,
indicating the impact velocity control mechanism in
our experimental setup works effectively. The
displacement vs. time curves measured in the two
experiments coincide, suggesting very good
repeatability.Before 2.0 ms of time period the
displacement response shows the plate is under bird
impact while after 2.0 ms the fluctuation in
displacement is just a result of the free rebound of
the plate. The free rebound displacement fluctuates
above zero, indicating the plate is deformed
plastically after impacted by the bird. The strain
measurement in the two experiments as well as the
Kinetic energy absorption measurements show good
repeatability.
(a) CEL simulation with bird velocity of 60 ms-1
(b) SPH simulation with bird velocity of 60 ms-1
Figure 5-1: shows a 1.8 kg bird impacting the
10 mm thick AlCu4Mg1 plate at a velocity of
60 m/s
CEL model SPH model
Advantages Uses mesh
and gives
absolute
values.
No mesh
distortion,
constant time
step
Simple model
generation
Numerically
stable
simulations.
Impactor
boundary
clearly
defined
Good
representation
of splashing
behavior
Complex bird
splitting can
be simulated
Lower
computational
cost
Disadvantages Higher
computational
cost
Model
generation
more
complex
Hourglass
problems
No tensile
behavior
Splashing
behavior
difficult to
represent with
CEL
No clear outer
boundary.
Fine mesh
necessary in
impact zone:
expensive.
5.1.2 Dynamic Responses:
Kinetic energy absorption vs time
Deflection vs timeStrain Energy vs time
(a) Graphs of CEL method with bird velocity 60ms-
1.
(c) Graphs of SPH method with bird velocity 60ms-
1.
Fig 5.1.1: Graphs of kinetic energy, strain
energy and displacement at 60ms-1.
5.2 Test 2:
Fig. displays the experimental results for test No. 2.
The actual impact velocities are 70 m/ s on both
SPH Bird Model and CEL Bird. These values are
very close to the expected impact velocity of 70 m/s.
The displacement vs. time curves are measured in
the two experiments show good agreement.
The strain measurements and the Kinetic energy
absorption measurements in the two experiments
show good repeatability.
(a) CEL simulation with bird velocity of 70ms-1
(b) SPH simulation with bird velocity of 70ms-1.
Fig 5.2.0 : shows a 1.8 kg bird impacting the 10
mm thick AlCu4Mg1 plate at a velocity of 70
m/s
5.2.1 Dynamic Responses:
Kinetic energy absorption vs time
Deflection vs timeStrain Energy vs time
0.E+00
5.E+01
1.E+02
2.E+02
2.E+02
0.E+00
7.E-05
1.E-04
2.E-04
3.E-04
3.E-04
4.E-04
5.E-04
5.E-04
6.E-04
7.E-04
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9.E-04
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1.E-03
1.E-03
1.E-03
1.E-03
1.E-03
1.E-03
1.E-03
Ener
gy
Time
Kinetic energy: ALLKE for Whole Model
-5.E+00
0.E+00
5.E+00
1.E+01
2.E+01
0.E+00
7.E-05
1.E-04
2.E-04
3.E-04
3.E-04
4.E-04
5.E-04
5.E-04
6.E-04
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1.E-03
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1.E-03
Ener
gy
Time
Strain energy: ALLSE for Whole Model
-1.E-02
-5.E-03
0.E+00
0.E+00
8.E-05
2.E-04
2.E-04
3.E-04
4.E-04
5.E-04
5.E-04
6.E-04
7.E-04
8.E-04
8.E-04
9.E-04
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1.E-03
1.E-03
1.E-03
1.E-03
1.E-03
1.E-03
2.E-03
Dis
pla
cem
ent
Time
From Field Data: U:U2 at part instance PANEL-1 node 2678
0.E+002.E+054.E+056.E+058.E+051.E+06
0.E+00
4.E-03
7.E-03
1.E-02
1.E-02
2.E-02
2.E-02
3.E-02
3.E-02
3.E-02
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4.E-02
4.E-02
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5.E-02
5.E-02
6.E-02
6.E-02
6.E-02
7.E-02
7.E-02
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Ene
rgy
Time
Kinetic energy: ALLKE for Whole Model
0.E+002.E+044.E+046.E+048.E+041.E+051.E+05
0.E+00
4.E-03
7.E-03
1.E-02
1.E-02
2.E-02
2.E-02
3.E-02
3.E-02
3.E-02
4.E-02
4.E-02
4.E-02
5.E-02
5.E-02
5.E-02
6.E-02
6.E-02
6.E-02
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8.E-02
Stra
in E
ner
gy
Time
Strain energy: ALLSE for Whole Model
-5.E+01
-4.E+01
-3.E+01
-2.E+01
-1.E+01
0.E+00
0.E+00
4.E-04
8.E-04
1.E-03
2.E-03
2.E-03
2.E-03
3.E-03
3.E-03
4.E-03
4.E-03
4.E-03
5.E-03
5.E-03
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6.E-03
6.E-03
7.E-03
7.E-03
8.E-03
8.E-03
Dis
pla
cem
ent
Time
From Field Data: U:U3 at part instance PANEL node 2279
0.E+00
5.E+01
1.E+02
2.E+02
2.E+02
3.E+02
0.E+00
8.E-05
2.E-04
2.E-04
3.E-04
4.E-04
5.E-04
5.E-04
6.E-04
7.E-04
8.E-04
8.E-04
9.E-04
1.E-03
1.E-03
1.E-03
1.E-03
1.E-03
1.E-03
1.E-03
2.E-03
Ener
gy
Time
Kinetic energy: ALLKE for Whole Model
-5.E+00
0.E+00
5.E+00
1.E+01
2.E+01
2.E+01
0.E+00
8.E-05
2.E-04
2.E-04
3.E-04
4.E-04
5.E-04
5.E-04
6.E-04
7.E-04
8.E-04
8.E-04
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1.E-03
1.E-03
1.E-03
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1.E-03
1.E-03
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2.E-03
Ener
gy
Time
Strain energy: ALLSE for Whole Model
(a) graphs of bird velocity 70m-1 in CEL method.
(b) graphs of bird velocity 70ms-1 in SPH method.
Fig 5.2.1 : graphs of kinetic energy, strain
energy and displacement at 70ms-1.
5.3 Test 3:
Fig. displays the experimental results for test No. 3.
The actual impact velocities are 80 m/ s on both
SPH Bird Model and CEL Bird. These values are
very close to the expected impact velocity of 80 m/s.
The displacement vs. time curves measured in the
two experiments coincide.
Before 2.0 ms of time period the displacement
response shows the plate is under bird impact while
after 2.0 ms the fluctuation in displacement is just a
result of the free rebound of the plate. The free
rebound displacement fluctuates above zero,
indicating the plate is deformed plastically after
impacted by the bird. The strain measurement in the
two experiments as well as the Kinetic energy
absorption measurements show good repeatability.
(a) CEL simulation with bird velocity 80ms-1.
(b) SPH simulation with bird velocity 80ms-1.
Fig 5.3.1: shows a 1.8 kg bird impacting the 10
mm thick AlCu4Mg1 plate at a velocity of 80
m/s
5.3.1 Dynamic Responses:
Kinetic energy absorption vs time
Deflection vs time
Strain Energy vs time
-1.E-02
-1.E-02
-8.E-03
-6.E-03
-4.E-03
-2.E-03
0.E+00
0.E+00
8.E-05
2.E-04
2.E-04
3.E-04
4.E-04
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5.E-04
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7.E-04
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8.E-04
9.E-04
1.E-03
1.E-03
1.E-03
1.E-03
1.E-03
1.E-03
1.E-03
2.E-03
0.E+00
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6.E+05
8.E+05
1.E+06
1.E+06
1.E+06
0.E+00
4.E-04
9.E-04
1.E-03
2.E-03
2.E-03
3.E-03
3.E-03
4.E-03
4.E-03
4.E-03
5.E-03
5.E-03
6.E-03
6.E-03
7.E-03
7.E-03
7.E-03
8.E-03
Ener
gy
Time
Kinetic energy: ALLKE for Whole Model
0.E+00
2.E+04
4.E+04
6.E+04
8.E+04
1.E+05
1.E+05
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2.E+05
0.E+00
4.E-04
8.E-04
1.E-03
2.E-03
2.E-03
2.E-03
3.E-03
3.E-03
4.E-03
4.E-03
4.E-03
5.E-03
5.E-03
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6.E-03
6.E-03
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7.E-03
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8.E-03
Ene
rgy
Time
Strain energy: ALLSE for Whole Model
-5.E+01
-4.E+01
-3.E+01
-2.E+01
-1.E+01
0.E+00
1.E+01
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4.E-04
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2.E-03
2.E-03
2.E-03
3.E-03
3.E-03
4.E-03
4.E-03
4.E-03
5.E-03
5.E-03
6.E-03
6.E-03
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Dis
pla
cem
en
t
Time
0.E+00
5.E+01
1.E+02
2.E+02
2.E+02
3.E+02
3.E+02
0.E+00
8.E-05
2.E-04
2.E-04
3.E-04
4.E-04
5.E-04
6.E-04
7.E-04
7.E-04
8.E-04
9.E-04
1.E-03
1.E-03
1.E-03
1.E-03
1.E-03
1.E-03
1.E-03
Ener
gy
Time
Kinetic energy: ALLKE for Whole Model
-5.E+00
0.E+00
5.E+00
1.E+01
2.E+01
2.E+01
3.E+01
3.E+01
0.E+00
8.E-05
2.E-04
2.E-04
3.E-04
4.E-04
5.E-04
6.E-04
7.E-04
7.E-04
8.E-04
9.E-04
1.E-03
1.E-03
1.E-03
1.E-03
1.E-03
1.E-03
1.E-03
Ener
gy
Time
Strain energy: ALLSE for Whole Model
(a) graphs of bird velocity 80m-1 in CEL method.
(b) graphs of bird velocity 80ms-1 in SPH method.
Fig 5.3.1: graphs of kinetic energy, strain
energy and displacement at 80ms-1.
5.4 Test 04:
Fig. displays the experimental results for test No. 4.
The actual impact velocities are 90 m/ s on both
SPH Bird Model and CEL Bird. These values are
very close to the expected impact velocity of 90 m/s.
The displacement vs. time curves measured in the
two experiments coincide.
Before 2.0 ms of time period the displacement
response shows the plate is under bird impact while
after 2.0 ms the fluctuation in displacement is just a
result of the free rebound of the plate. The free
rebound displacement fluctuates above zero,
indicating the plate is deformed plastically after
impacted by the bird. The strain measurement in the
two experiments as well as the Kinetic energy
absorption measurements show good repeatability.
(a) CEL simulation with bird velocity 90ms-1.
(b) SPH simulation with bird velocity 90ms-1.
Fig 5-7: shows a 1.8 kg bird impacting the 10 mm
thick AlCu4Mg1 plate at a velocity of 90 m/s.
5.4.1 Dynamic Responses:
Kinetic energy absorption vs time
Deflection vs time
Strain Energy vs time
-1.E-02
-1.E-02
-1.E-02
-8.E-03
-6.E-03
-4.E-03
-2.E-03
0.E+00D
isp
lace
men
t
Time
_U:U2 PI: PANEL-1 N: 2678
0.E+002.E+054.E+056.E+058.E+051.E+061.E+061.E+062.E+06
0.E+00
4.E-04
9.E-04
1.E-03
2.E-03
2.E-03
3.E-03
3.E-03
4.E-03
4.E-03
4.E-03
5.E-03
5.E-03
6.E-03
6.E-03
7.E-03
7.E-03
7.E-03
8.E-03
Ener
gy
Time
Kinetic energy: ALLKE for Whole Model
0.E+00
5.E+04
1.E+05
2.E+05
2.E+05
0.E+00
4.E-04
9.E-04
1.E-03
2.E-03
2.E-03
3.E-03
3.E-03
4.E-03
4.E-03
4.E-03
5.E-03
5.E-03
6.E-03
6.E-03
7.E-03
7.E-03
7.E-03
8.E-03
Ene
rgy
Time
Strain energy: ALLSE for Whole Model
-6.E+01
-5.E+01
-4.E+01
-3.E+01
-2.E+01
-1.E+01
0.E+00
Dis
pla
cem
en
t
Time
From Field Data: U:U3 at part instance PART-2-1 node 2279
050100150200250300350400
0
7.55008E-05
0.000150289
0.000225078
0.000300578
0.000375365
0.000450152
0.000525653
0.000600443
0.000675233
0.000750023
0.000825412
0.000900664
0.000975282
0.001050243
0.001125023
0.001200484
0.001275244
0.001350002
0.001425428
0.0015
Ener
gy
Time
Kinetic energy: ALLKE for Whole Model
-5.E+00
0.E+00
5.E+00
1.E+01
2.E+01
2.E+01
3.E+01
3.E+01
4.E+01
0.E+00
8.E-05
2.E-04
2.E-04
3.E-04
4.E-04
5.E-04
6.E-04
7.E-04
7.E-04
8.E-04
9.E-04
1.E-03
1.E-03
1.E-03
1.E-03
1.E-03
1.E-03
1.E-03
Axi
s Ti
tle
Axis Title
Strain energy: ALLSE for Whole Model
(a) Graphs of bird velocity 90m-1 in CEL method.
(b) graphs of bird velocity 90ms-1 in SPH
method.
Fig 5.4.1: graphs of kinetic energy, strain
energy and displacement at 90ms-1.
5.5 Test 05:
Fig. 05 displays the experimental results for test No.
5. The actual impact velocities are 100 m/ s on both
SPH Bird Model and CEL Bird. These values are
very close to the expected impact velocity of 100
m/s. The displacement vs. time curves measured in
the two experiments coincide.
Before 2.0 ms of time period the displacement
response shows the plate is under bird impact while
after 2.0 ms the fluctuation in displacement is just a
result of the free rebound of the plate. The free
rebound displacement fluctuates above zero,
indicating the plate is deformed plastically after
impacted by the bird. The strain measurement in the
two experiments as well as the Kinetic energy
absorption measurements show good repeatability.
CEL simulation with bird velocity of 100ms-1.
SPH simulation bird velocity of 100ms-1.
Fig 5-9: shows a 1.8 kg bird impacting the 10 mm
thick AlCu4Mg1 plate at a velocity of 100 m/s.
5.5.1 Dynamic Responses:
Kinetic energy absorption vs time
Deflection vs time
Strain Energy vs time
(a) graphs of bird velocity 100m-1 in CEL method.
-2.E-02
-2.E-02
-1.E-02
-5.E-03
0.E+00D
Isp
lace
men
t
Time
From Field Data: U:U2 at part instance PANEL-1 node 2678
0.E+00
5.E+05
1.E+06
2.E+06
2.E+06
3.E+06
0.E+00
4.E-04
9.E-04
1.E-03
2.E-03
2.E-03
3.E-03
3.E-03
4.E-03
4.E-03
4.E-03
5.E-03
5.E-03
6.E-03
6.E-03
7.E-03
7.E-03
7.E-03
8.E-03
Ener
gy
Time
Kinetic energy: ALLKE for Whole Model
0.E+00
5.E+04
1.E+05
2.E+05
2.E+05
3.E+05
0.E+00
4.E-04
8.E-04
1.E-03
2.E-03
2.E-03
2.E-03
3.E-03
3.E-03
4.E-03
4.E-03
4.E-03
5.E-03
5.E-03
6.E-03
6.E-03
6.E-03
7.E-03
7.E-03
8.E-03
8.E-03
Ene
rgy
Time
Strain energy: ALLSE for Whole Model
-7.E+01
-6.E+01
-5.E+01
-4.E+01
-3.E+01
-2.E+01
-1.E+01
0.E+00
0.E+00
4.E-04
8.E-04
1.E-03
2.E-03
2.E-03
2.E-03
3.E-03
3.E-03
4.E-03
4.E-03
4.E-03
5.E-03
5.E-03
6.E-03
6.E-03
6.E-03
7.E-03
7.E-03
8.E-03
8.E-03
Dis
pla
cem
en
t
Time
From Field Data: U:U3 at part instance PANNEL node 2279
0.E+005.E+011.E+022.E+022.E+023.E+023.E+024.E+024.E+025.E+025.E+02
0.E+00
8.E-05
2.E-04
2.E-04
3.E-04
4.E-04
5.E-04
5.E-04
6.E-04
7.E-04
8.E-04
8.E-04
9.E-04
1.E-03
1.E-03
1.E-03
1.E-03
1.E-03
1.E-03
1.E-03
2.E-03
Ene
rgy
Time
Kinetic energy: ALLKE for Whole Model
-5.E+00
0.E+00
5.E+00
1.E+01
2.E+01
2.E+01
3.E+01
3.E+01
4.E+01
0.E+00
8.E-05
2.E-04
2.E-04
3.E-04
4.E-04
5.E-04
5.E-04
6.E-04
7.E-04
8.E-04
8.E-04
9.E-04
1.E-03
1.E-03
1.E-03
1.E-03
1.E-03
1.E-03
1.E-03
2.E-03
Ener
gy
Time
Strain energy: ALLSE for Whole Model
-3.E-02
-2.E-02
-2.E-02
-1.E-02
-5.E-03
0.E+00
0.E+00
8.E-05
2.E-04
2.E-04
3.E-04
4.E-04
5.E-04
5.E-04
6.E-04
7.E-04
8.E-04
8.E-04
9.E-04
1.E-03
1.E-03
1.E-03
1.E-03
1.E-03
1.E-03
1.E-03
2.E-03
Ener
gy
Time
From Field Data: U:U2 at part instance PANEL-1 node 2678
Graphs of bird velocity 100ms-1 in SPH method.
Fig 5.5.1: graphs of kinetic energy, strain
energy and displacement at 100ms-1.
6.0 Result:
Comparisons of results from different tests
In this section, the bird strike is simulated using the
Two-bird models CEL and SPH respectively. Fig
compares the simulation results with the
experimental measurements.
From the comparison of different properties of the
whole system when the bird velocity at 60 ms-1,
70ms-1,80 ms-1,90 ms-1,100 ms-1.
1. The curves of Kinetic Energy and Strain
Energy are behaving similar in sph and
experimet values are very near, whereas the
CEL mehtod is not providing values near to
the experimental values.
2. The displacement curve of CEL is Near to
the experimental values but it again
discontinued at the peak values wihout
exhibiting any rebounce framework in the
plate.
3. The strain energy curve of CEL is Near to
the experimental values but it again
discontinued at the peak values wihout
exhibiting any rebounce framework in the
plate.
7.0 Conclusion
The main purpose is to analyse a bird strike on
Aircraft structure using Abaqus/Explicit. Explicit
finite element method is used to analyze this type of
short duration highly nonlinear impact problem.
1. Within the scope of this thesis study,
detailed information about the bird crash
and the related regulations will be reached
and an analysis and evaluation of the bird
crash events will be presented.
2. The advantages and disadvantages of
available solution techniques such as (CEL)
Coupled Eulerian Legrangian and SPH
(Smooth Particle Hydrodynamics) methods
used in bird strike analyzes will be
examined and compared.
3. In addition, soft body impactor which is a
bird in this study, is going to be modeled
according to literature review. Cylindrical
bird geometry will be modeled by using
SPH (Smooth Particle Hydrodynamics)
solution technique.
4. The SPH method will be modeled again
from a previous work on bird strike and the
bird strike phenomenon will be examined
on a Aircraft structure which will be taken
as an example after the validity of the
parameters is proved. In this study, bird
strike analysis on a 10 mm thick AlCu4Mg1
plate will be carried out,
5. The effect of the change of solution net
density and the material thickness will be
examined.
6. Strain-strain amounts on the Crash will be
compared with the material properties and a
comment will be tried to be made.
0.E+00
5.E+05
1.E+06
2.E+06
2.E+06
3.E+06
0.E+00
4.E-04
7.E-04
1.E-03
1.E-03
2.E-03
2.E-03
3.E-03
3.E-03
3.E-03
4.E-03
4.E-03
4.E-03
5.E-03
5.E-03
5.E-03
6.E-03
6.E-03
6.E-03
7.E-03
7.E-03
8.E-03
8.E-03
Ener
gy
Time
Kinetic energy: ALLKE for Whole Model
0.E+00
5.E+04
1.E+05
2.E+05
2.E+05
3.E+05
3.E+05
0.E+00
4.E-04
7.E-04
1.E-03
1.E-03
2.E-03
2.E-03
3.E-03
3.E-03
3.E-03
4.E-03
4.E-03
4.E-03
5.E-03
5.E-03
5.E-03
6.E-03
6.E-03
6.E-03
7.E-03
7.E-03
8.E-03
8.E-03
Ener
gy
TIme
Strain energy: ALLSE for Whole Model
-7.E+01
-6.E+01
-5.E+01
-4.E+01
-3.E+01
-2.E+01
-1.E+01
0.E+00
1.E+01
0.E+00
4.E-04
8.E-04
1.E-03
2.E-03
2.E-03
2.E-03
3.E-03
3.E-03
4.E-03
4.E-03
4.E-03
5.E-03
5.E-03
6.E-03
6.E-03
6.E-03
7.E-03
7.E-03
8.E-03
8.E-03
Dis
pla
cem
en
t
Time
From Field Data: U:U3 at part instance PANNEL node 2279
8.0 References:
CCAR-25-R3 Airworthiness Standards, Transport
Category Aircrafts, Civil Aviation Administration of
China, 2001.
I. Smojver, D. Ivančević, Numerical simulation of
bird strike damage prediction in airplane flap
structure, Compos. Struct. 92 (2010) 2016–2026.
A. Airoldi, D. Tagliapiera, Bird Impact Simulation
against a Hybrid Composite and Metallic Vertical
Stabilizer, (2001) AIAA-2001-1390.
J. Reglero, M. Rodriíguez-Pérez, E. Solórzano, et
al., Aluminium foams as a filler for leading edges:
improvements in the mechanical behavior under bird
strike impact tests, Mater. Des. 32 (2) (2011) 907–
910.
J. Liu, Y.L. Li, X.C. Yu, et al., A novel design for
reinforcing the aircraft tail leading edge structure
against bird strike, Int. J. Impact Eng. 105 (2017)
89–101.
M.Y. Zhao, J.J. Li, Efficiency metallic leading edge
structure bird strike resistant design, Adv. Mater.
Res. 338 (2011) 84–89.
A. Riccio, R. Cristiano, S. Saputo, et al., Numerical
methodologies for simulating bird-strike on
composite wings, Compos. Struct. 202 (2008) 590–
602.
M.A. Lavoie, A. Gakwaya, M.N. Ensan, et al.,
Review of existing numerical methods and
validation procedure available for bird strike
modeling, International conference on
computational & experimental engineering and
sciences, 2 2007, pp. 111–118.
Y.J. Liu, Z. Li, Q. Sun, et al., Separation dynamics
of large-scale fairing section: a fluid–structure
interaction study, Proc. Inst. Mech. Eng. G J.
Aerosp. Eng. 227 (2013) 1767–1779.
R. Jain, K. Ramachandra, Bird impact analysis of
pre-stressed fan blades using explicit finite element
code, Proceedings of the International Gas Turbine
Congress Tokyo, 2003.
M. Guida, F. Marulo, M. Meo, et al., SPH–
Lagrangian study of bird impact on leading edge
wing, Compos. Struct. 93 (2011) 1060–1071.
J. Liu, Y.L. Li, F. Xu, The numerical simulation of a
bird-impact on an aircraft windshield by using the
SPH method, Adv. Mater. Res. 33 (2008) 851–856.
R. Budgey, The Development of Artificial Bird
Designs for Bird-Strike Resistance Testing,
IBSC25/WP-IE3, Amsterdam, 2000.
J. Liu, Y.L. Li, Inversion on the constants of bird
body constitutive model I: study on bird impact
plane test, Journal of Aeronautics 32 (5) (2011)
802–811.
S.C. Fei, Q. Sun, Investigation on parameters
calibration for the J-C failure model of aluminum
alloy, Computer Simulation 30 (9) (2013) 46–50.
N. Li, Y.L. Li, W.G. Guo, Comparison of
mechanical properties and their temperature
dependencies for three aluminum alloys under
dynamic load, Acta Aeronauticaet Astronautical
Sinica 29 (4) (2008) 903–908.
Y.J. Liu, Q. Sun, A dynamic ductile fracture model
on the effects of pressure, Lode angle and strain rate,
Mater. Sci. Eng. A 589 (2014) 262–270.
Y.J. Liu, Q. Sun, X.L. Fan, et al., A stress-invariant
based multi-parameters ductile progressive fracture
model, Mater. Sci. Eng. A 576 (2013) 337–345.
X. Liang, Damage accumulation and fracture
initiation in uncracked ductile solids subject to
triaxial loading, Int. J. Solids Struct. 44 (2007)
5163–5181.
M.Dakshina Moorthy is currently
pursuing her M.Tech (Mechanical Engineering) Machine
Design domain in Sri Vani Group of Institutions, Chevuturu Village,G.Konduru Mandalam,Krishna
District, Vijayawada,Andhra Pradesh.
He completed her graduation in Sri Venkateswara Colleeg of
Engineering,Tirupathi,Andhra Pradesh. His areas of interests
includes Machine Design, Advanced Strength of Materials, Finete
Element analysis.
Mr.T.Chakravarhi was born in 1985.he
received his mtech &Btech from jntuh in (2014&2006).at
present he is working as assistant professor and head
Mech department at srivani group of
institutions,chevutur.he has six years of teaching
experience and 8 years of industrial experience.