Upload
divya-srinivasan
View
7
Download
2
Tags:
Embed Size (px)
DESCRIPTION
useful notes on aeroelasticity
Citation preview
Kolonay 1
CRD
Computational AeroelasticityThe Cultural and Convention Center
METUInonu bulvari
Ankara, Turkey
Sponsored by:RTA-NATO
The Applied Vehicle Technology Panel
presented byR.M. Kolonay Ph.D.
General Electric Corporate Research & Development CenterAnkara, Turkey Oct.. 1-5, 2001
Kolonay 2
CRD
Introduction- Fluid-Structure Interactions
Aeroelasticity- Aeroelastic analysis/design in an MDA/MDO Environment
Static Aeroelasticity
Dynamic Aeroelasticity
Commercial Programs with Aeroelastic Analysis/DesignCapabilities
Presentation Outline
Kolonay 3
CRD
Dynamic Aeroelastic Phenomena
Dynamic Response
Limit Cycle Oscillations (LCO)
Buffet
Flutter
Dynamic Aeroelasticity
Solutions found in time, frequency, and Laplace domain usuallywith generalized coordinates
Kolonay 4
CRD Dynamic Aeroelasticity
Dynamic Response
Transient response due to a rapidly applied load.
Atmospheric Turbulence- Continuous random- Discrete random (gust)
Landing loads Snap maneuvers Store Separation
Kolonay 5
CRD Dynamic Aeroelasticity
Limit Cycle Oscillations
Typically caused by shock induced oscillations on a surface or flow/shocks attaching/detaching from a surface trailing edge.
Panel Flutter Control Surface Buzz Store/Wing configurations
Reduces structural life
Usually requires nonlinear flow conditions and possibly nonlinearstructures (cs hinge stiffness)
Kolonay 6
CRD Dynamic Aeroelasticity
BuffetResponse due to time-dependent separated flows (usually vortical)impinging on structural surfaces.
Bluffed bodies on horizontal and vertical surfaces Wings, strakes etc.. on vertical tails (often a twin tail prob-
lem)
Reduces structural life
Requires nonlinear aerodynamics to capture phenomena
Kolonay 7
CRD Dynamic Aeroelasticity
Flutter
Dynamic instability where-by the system extracts energy from thefree stream flow producing a divergent response.
Usually resultant of coupling of 2 or more structural modes- Wing bending and torsion- Wing bending control surface hinge torsion- Wing torsion fuselage bending- Horizontal or vertical tail and fuselage
Divergent behavior can occur within a few cycles and be cata-strophicTheodore Von Karman is said to have remarked that
some men fear flutter because they do not understand it, whileothers fear it because they do[8]
Kolonay 8
CRD
M
o
t
i
o
n
M
o
t
i
o
n
M
o
t
i
o
n
Stable (A)
Neutral (B)
Unstable (C)F
r
e
q
u
e
n
c
y
A
BC
Torsion Mode
Bending Mode
Dynamic Aeroelasticity
FlutterTime Histories
Modal Coupling
Dynamic Pressure
Kolonay 9
CRD Dynamic Aeroelasticity
From ro(20)
let(21)
Whe rEq. ( b
(22)For s so
(23)
)
B+
u
(23) s lem the ae
re20) can
tability
F t(
Mu
M
can beFlutterelastic EOM
epresents motion independent external forcese written as
lve the homogenous equation from some initial state.
Mu Ku+ F u u u t, , ,( )=
F u u u t, , ,( ) F u u u, ,( ) F t( )+=
u Ku+ Q1[ ] u Q2[ ]u Q3[ ]u F t( )+ + +=
Bu Ku+ + Q1[ ] u Q2[ ]u Q3[ ]u+ +=
olved by time integration or as an eigenvalue prob
Kolonay 10
CRD
Tran (2unst ero
(24)Assu at us
(25)With in nto(24)
(26)
hh
hh
Dynamic Aeroelasticitysformeady a
me th
gives
M
qh{ }
MEigenvalue Solutions3) to modal coordinates and assume that thedynamics depend only on displacements
the structural response is separable and synchrono
dependent of time and .Substituting i
uh{ }
uh Buh
Khhuh12---V
2 Qhh[ ]uh+ + 0=
uh{ } qh{ }est
=
s i+=
s2 Bhhs Khh
12---V
2Qhh+ + qh{ } 0=
Kolonay 11
CRD
6 a ff-
ma ts
co
- GOft
Do
al
Sta
KKPP
Dynamic AeroelasticityEq. (2 All m
ness
to be
-
phase-
Sever-
-
-
-
-
Qhh) is the basic flutter eigenvalue equationtrices can be expressed as real but the aeroelastic sti
trix is unsymmetric causing roo
mplex conjugate pairs.eneralized unsteady aerodynamic forces
en assumed harmonic cast in frequency domain with amplitude and
ublet Lattice, CPM, Mach Box, Strip Theory
solutions exist for solving (26)Method
Method Method
Methodte space
Khh12---V
2Qhh
EK
Kolonay 12
CRD
can pr
7)
- sel trea
- ref i-chplex
, gene
-
- free sity
- redu ncy
- eig f m
- dam
s
2
V
bp k (Mhh B
QhhI ]=
k
qhi 1
Dynamic Aeroelasticity be ex
ected frees
erence sem - com
,
stream den
ced freque
envector o
ping factor
Vb----
2p
i+ )hh Khh
QR iQ+[P-K Flutter Solutionessed as . (26) becomes
(2
m speed
ord response frequency and eigenvalueralized mass, damping, stiffness matrices
generalized aerodynamic matrix
,
odal coordinates
sVkb------ i+( )
Vb---- p= =
MhhVb---- pBhh Khh
V2
2----------Q k( )hh+ + qh 0=
k bV-------=
Kolonay 13
CRD
P-K Method Comments
Matrices are real but non-symmetric yielding complex roots.
Flutter equation only true when , an estimate elsewhere Mode switching often occurs making results interpretation difficult
depends on Mach number and reduced frequency
Solution requires to be a continuous function of .
- Results in curve fitting which can cause errors
Above formulation does not allow User responsible for determining match point solutions
0=
Qhh Qhh M k,( )
Qhh kQhh
k 0=
Dynamic Aeroelasticity
Kolonay 14
CRD
AGARD 445.6 Flutter Calculations
X
Y
Z
31.38
27.48
23.57
19.67
15.77
11.86
7.958
4.055
.1511
-3.753
-7.656
-11.56
-15.46
-19.37
-23.27
-27.17
X
Y
ZX
YZ
X
YZ
Dynamic Aeroelasticity
X
Y
Z
71.52
65.25
58.97
52.69
46.42
40.14
33.87
27.59
21.31
15.04
8.761
2.485
-3.791
-10.07
-16.34
-22.62
X
Y
ZX
YZ
X
YZ
Mode 4, = 89.94 Hz.
X
Y
Z
25.09
20.38
15.68
10.97
6.269
1.565
-3.139
-7.843
-12.55
-17.25
-21.96
-26.66
-31.36
-36.07
-40.77
-45.48
X
Y
ZX
YZ
X
YZ
Mode 2, = 37.12 Hz.
X
Y
Z
27.92
26.05
24.19
22.32
20.45
18.59
16.72
14.85
12.98
11.12
9.250
7.383
5.516
3.649
1.782
-.08551
X
Y
ZX
YZ
X
YZ
Mode Shapes and frequencies
Mode 3, = 50.50 Hz.Mode 1, = 9.63 Hz.
Kolonay 15
CRD Dynamic Aeroelasticity
AGARD 445.6 Time Integration Response
0.0 0.1 0.2 0.3 0.4
-0.0015
-0.0010
-0.0005
0.0000
0.0005
0.0010
0.0015
Time (sec)
G
e
n
e
r
a
l
i
z
e
d
D
i
s
p
l
a
c
e
m
e
n
t
1= 13.06821= 88.352(Hz)2= 5.94082= 52.285(Hz)3= 24.10023= 30.268(Hz)4= .16874= 15.574(Hz)
DATAFITERROR
0.0 0.1 0.2 0.3 0.4
-0.015
-0.010
-0.005
0.000
0.005
0.010
0.015
Time (sec)
G
e
n
e
r
a
l
i
z
e
d
D
i
s
p
l
a
c
e
m
e
n
t
1= -.03661= 15.561(Hz)2= 32.09162= 30.286(Hz)3= 445.60373= .612(Hz)4= 4.77384= 52.054(Hz)
DATAFITERROR
0.0 0.1 0.2 0.3 0.4
-0.0020
-0.0010
0.0000
0.0010
0.0020
0.0030
Time (sec)
G
e
n
e
r
a
l
i
z
e
d
D
i
s
p
l
a
c
e
m
e
n
t
1= 5.76351= 52.269(Hz)2= 25.91592= 30.188(Hz)3= .03963= 15.564(Hz)4= 12.46104= 88.338(Hz)
DATAFITERROR
0.0 0.1 0.2 0.3 0.4
-0.0040
-0.0030
-0.0020
-0.0010
0.0000
0.0010
0.0020
0.0030
0.0040
Time (sec)
G
e
n
e
r
a
l
i
z
e
d
D
i
s
p
l
a
c
e
m
e
n
t
1= .02821= 15.569(Hz)2= 25.87332= 30.095(Hz)3= 5.76883= 52.242(Hz)4= 12.07914= 88.547(Hz)
DATAFITERROR
Mode 1 Mode 3
Mode 2 Mode 4
M 0.901 q, 0.66psi U, 11908 in/sec= = =
Kolonay 16
CRD Dynamic Aeroelasticity
AGARD 445.6 Time Response Integration
0.0 0.1 0.2 0.3 0.4
-0.0020
-0.0010
0.0000
0.0010
0.0020
0.0030
Time (sec)
G
e
n
e
r
a
l
i
z
e
d
D
i
s
p
l
a
c
e
m
e
n
t
1= 5.76351= 52.269(Hz)2= 25.91592= 30.188(Hz)3= .03963= 15.564(Hz)4= 12.46104= 88.338(Hz)
DATAFITERROR
0.0 0.1 0.2 0.3 0.4
-0.0015
-0.0010
-0.0005
0.0000
0.0005
0.0010
0.0015
Time (sec)
G
e
n
e
r
a
l
i
z
e
d
D
i
s
p
l
a
c
e
m
e
n
t
1= 13.06821= 88.352(Hz)2= 5.94082= 52.285(Hz)3= 24.10023= 30.268(Hz)4= .16874= 15.574(Hz)
DATAFITERROR
0.0 0.1 0.2 0.3 0.4
-0.0040
-0.0030
-0.0020
-0.0010
0.0000
0.0010
0.0020
0.0030
0.0040
Time (sec)
G
e
n
e
r
a
l
i
z
e
d
D
i
s
p
l
a
c
e
m
e
n
t
1= .02821= 15.569(Hz)2= 25.87332= 30.095(Hz)3= 5.76883= 52.242(Hz)4= 12.07914= 88.547(Hz)
DATAFITERROR
0.0 0.1 0.2 0.3 0.4
-0.015
-0.010
-0.005
0.000
0.005
0.010
0.015
Time (sec)
G
e
n
e
r
a
l
i
z
e
d
D
i
s
p
l
a
c
e
m
e
n
t
1= -.03661= 15.561(Hz)2= 32.09162= 30.286(Hz)3= 445.60373= .612(Hz)4= 4.77384= 52.054(Hz)
DATAFITERROR
M 0.901 q, 0.67psi U, 11998 in/sec= = =
Mode 1
Mode 4Mode 2
Mode 3Vf = 11,971 in/sec
rad f 90=
Kolonay 17
CRD
AGARD 445.6 P-K Flutter Solution
6000 8000 10000 12000 14000
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
MODE 1MODE 2MODE 3MODE 4
Dynamic Aeroelasticity
D
a
m
p
i
n
g
r
a
t
i
o
(
g
)
Velocity (V in/sec)
Velocity vs. Damping
Vf =1181 in/sec
Kolonay 18
CRD
AGARD 445.6 P-K Flutter Solution
-0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2
100
200
300
400
500
MODE 1MODE 2MODE 3MODE 4
445.6 Wing Damping Ratio versus Frequency
(M= .901, = 0.00, = 9.307E-09 slugs/ in )
Dynamic Aeroelasticity
F
r
e
q
u
e
n
c
y
(
r
a
d
i
a
n
s
)
Damping ratio (g)
Velocity Root Locus
rad f 96=
Kolonay 19
CRD Dynamic Aeroelasticity
AGARD 445.6 P-K Flutter Solution
6000 8000 10000 12000 14000
100
200
300
400
500
MODE 1MODE 2MODE 3MODE 4
Velocity vs. FrequencyF
r
e
q
u
e
n
c
y
(
r
a
d
i
a
n
s
)
Velocity (V in/sec)
Kolonay 20
CRD Aeroelastic Software
Global Aeroelastic Software Developments MSC/NASTRAN (U.S.) UAI/ASTROS (recently bought by MSC) (U.S.) UAI/NASTRAN (U.S.) ELFINI (France, Dessault) LAGRANGE (Germany, formerly MBB) STARS (Great Britain, RAE) OPTSYS (Sweden, SAAB) COMPASS (China) ARGON (Russia, Central Aerohydrodynamic Institute)
Kolonay 21
CRD Aeroelastic Software
y Sub
Sup
adSub
SupStead-
-
Unste-
- MSC/NASTRANAerodynamicssonicDoublet Lattice (k=0)3-D panel Method (available in the near future)Bypass option for any AICersonicZONA51Bypass option for any AICAerodynamic databaseImport/export loads data
y AerodynamicsonicDoublet Lattice with body interferenceStrip TheoryersonicMach Box
Kolonay 22
CRD
turVer
A5 DFleCom esAbDivSleMuAerImpStruc-
Static-
-
-
-
-
-
-
-
- Piston TheoryZONA51
al Modelingy rich selection of FE
eroelastic AnalysisOF trim (no drag/thrust trim)xible increment analysis
putes rigid, restrained and unrestrained flexible stability derivativle to add experimental load correction factors to AICergence of restrained vehiclender body modelsltiple set selectable aerodynamic modelsoelastic databaseort/export loads data
Aeroelastic Software
Kolonay 23
CRD
mFreRanTraGuFlu
nteInfiThiFinBeaRig
osExt envi-nt
QDyna-
-
-
-
-
-
F-S I-
-
-
-
-
Pre-P-
ronmeic Aeroelasticityquency response analysisdom analysis
nsient analysisst (random and discrete 1-d)tter P-K, K, K-E (K-E allows k=0)
curve fits cubic through all points
rfacenite plate splinen plate splineite plate splinem splineid load Transfer
t Processingensive Flight Loads pre/post processing functionality in PATRAN
M k,( )
Aeroelastic Software
Kolonay 24
CRD Aeroelastic Software
/A y A
ub
up
adub
upUAIStead
- S
- S
Unste- S
- SSTROS Aeroelastic Capabilitieserodynamics
sonicUSSAERO (Woodward Aerodynamics, flat panel)QUADPAN (Lockheed Martin, 3-D panel)Bypass option for any AICMultiple set selectable aerodynamic models
ersonicUSSAERO (flat panel)QUADPAN (3-D panel)Bypass option for any AIC
y AerodynamicsonicDoublet LatticeersonicConstant Pressure Method (Apa, Northrop)
Kolonay 25
CRD
turMe s,
AFulComUseTrim
mGuFluSev
nteInfiStruc-
Static-
-
-
-
Dyna-
-
-
F-S I- al Modelingmbrane type FEM (Rods, Beams, Shear panels, Quadrilateral PlateComposites)
eroelastic Analysisl 6 DOF Trim
putes rigid and four types of flexible stability derivativesr defined loads Optimization
ic Aeroelasticityst Responsetter P-K (computes flutter velocity)eral choices for curve fits
rfacenite Plate spline
Q M k,( )
Aeroelastic Software
Kolonay 26
CRD
3-DBeaRig
ea sys--
-
-
Very tem surface splinem splineid load Transfer
sy to add user defined functionality and tailor the
Aeroelastic Software
Kolonay 27
CRD
1. Bis f, A -Wes-ley Pu Co2. We Fu sitySchoo ona3. Sm nd ry toAircra ture4. Nei HeASTR ore5. Ben Od ateAeroe mu Flow-Induc tio6. Far Sp ber1995.7. Ma . H il,1971.8. I.E. an nal ofAircra 18,
Referencesshley and Halfman Aeroelasticity, Dover Publications, Addisonmpany, Inc., 1995.ndamentals of Static and Dynamic Aeroelasticity, Purdue Univerutics and Astronautics, West Lafayette, IN 1992.
Wasserman, L. S., Application of Three Dimensional Flutter Theos, USAAF TR 4798, 1942.
rendeen, D.L., Venkayya, V.B., ASTROS Enhancements, Vol III-tical Manual, WL-TR-95-3006.dvar O., Fluid-Structure Coupling Requirements for Time-Accurlations, AD-Vol.53-3, Fluid-Structure Interaction, Aeroelasticity,n and Noise, Volume III ASME, 1997.ecial course on Parallel Computing in CFD, AGARD-R807, Octo
., The NASTRAN Theoretical Manual, NASA-SP-221(01), Apr
d W.H. Reed, III Historical Development of Aircraft Flutter, Jour No. 11, November 1981.plinghofblishingisshaar, l of Aerilg, B. aft Strucll, D.J., OS Thediksen, lastic Sied Vibrahat, C.,
cNeal, R
Garrickft, Vol.
Kolonay 28
CRD
9. Gru er ngthAnaly pt n,,AFFD 5-110. Ha J., byDeterm tera -889.11. Ne , M ndlerCorpo 15mman Asis and OL-TR-7ssig, H.inant I
ill, D.J.ration, 8ospace Corporation, An Automated Procedure for Flutter and Streimization of Aerospace Vehicles Volume I. Theory and Applicatio37.An Approximate True Damping Solution of the Flutter Equation tion, Journal of Aircraft, Vol. 8, No. 11, November 1971, pp. 885SC/Flight Loads and Dynamics Training,, The MacNeal-Schwe
Colorado Boulevard, Los Angeles, CA, August 1999.
References
Computational AeroelasticityThe Cultural and Convention CenterMETUInonu bulvariAnkara, TurkeySponsored by:RTA-NATOThe Applied Vehicle Technology Panelpresented byR.M. Kolonay Ph.D.General Electric Corporate Research & Development CenterAnkara, Turkey Oct.. 1-5, 2001 Introduction- Fluid-Structure Interactions Aeroelasticity- Aeroelastic analysis/design in an MDA/MDO Environment
Static Aeroelasticity Dynamic Aeroelasticity Commercial Programs with Aeroelastic Analysis/Design Capabilities
Presentation OutlineReferences1. Bisplinghoff, Ashley and Halfman Aeroelasticity, Dover Publications, Addison-Wesley Publishi...2. Weisshaar, Fundamentals of Static and Dynamic Aeroelasticity, Purdue University School of Ae...3. Smilg, B. and Wasserman, L. S., Application of Three Dimensional Flutter Theory to Aircraft S...4. Neill, D.J., Herendeen, D.L., Venkayya, V.B., ASTROS Enhancements, Vol III- ASTROS Theoretica...5. Bendiksen, Oddvar O., Fluid-Structure Coupling Requirements for Time-Accurate Aeroelastic Sim...6. Farhat, C., Special course on Parallel Computing in CFD, AGARD-R807, October 1995.7. MacNeal, R. H., The NASTRAN Theoretical Manual, NASA-SP-221(01), April, 1971.8. I.E. Garrick and W.H. Reed, III Historical Development of Aircraft Flutter, Journal of Aircr...9. Grumman Aerospace Corporation, An Automated Procedure for Flutter and Strength Analysis and O...10. Hassig, H.J., An Approximate True Damping Solution of the Flutter Equation by Determinant It...11. Neill, D.J., MSC/Flight Loads and Dynamics Training,, The MacNeal-Schwendler Corporation, 8...
ReferencesDynamic Aeroelastic Phenomena Dynamic Response Limit Cycle Oscillations (LCO) Buffet Flutter
Dynamic AeroelasticityFlutter
Dynamic AeroelasticityDynamic AeroelasticityDynamic ResponseTransient response due to a rapidly applied load. Atmospheric Turbulence- Continuous random- Discrete random (gust)
Landing loads Snap maneuvers Store Separation
Dynamic AeroelasticityLimit Cycle OscillationsTypically caused by shock induced oscillations on a surface or flow/ shocks attaching/detaching f... Panel Flutter Control Surface Buzz Store/Wing configurationsReduces structural lifeSolutions found in time, frequency, and Laplace domain usually with generalized coordinatesUsually requires nonlinear flow conditions and possibly nonlinear structures (cs hinge stiffness)
Dynamic AeroelasticityBuffetResponse due to time-dependent separated flows (usually vortical) impinging on structural surfaces. Bluffed bodies on horizontal and vertical surfaces Wings, strakes etc.. on vertical tails (often a twin tail problem)
Reduces structural life
Dynamic AeroelasticityFlutterDynamic instability where-by the system extracts energy from the free stream flow producing a div... Usually resultant of coupling of 2 or more structural modes- Wing bending and torsion- Wing bending control surface hinge torsion- Wing torsion fuselage bending- Horizontal or vertical tail and fuselage
Divergent behavior can occur within a few cycles and be catastrophicsome men fear flutter because they do not understand it, while others fear it because they do[8]
Dynamic AeroelasticityFlutterFrom the aeroelastic EOM(20)let
(21)Where represents motion independent external forcesEq. (20) can be written as
(22)For stability solve the homogenous equation from some initial state.
(23)
Eigenvalue SolutionsTransform (23) to modal coordinates and assume that the unsteady aerodynamics depend only on disp...(24)Assume that the structural response is separable and synchronous
(25)With independent of time and .Substituting into (24) gives
(26) Eq. (26) is the basic flutter eigenvalue equation All matrices can be expressed as real but the aeroelastic stiffness matrix is unsymmetric causi... - Generalized unsteady aerodynamic forces- Often assumed harmonic cast in frequency domain with amplitude and phase- Doublet Lattice, CPM, Mach Box, Strip Theory
Several solutions exist for solving (26)- Method- Method- Method- Method- State space
P-K Flutter Solutioncan be expressed as . (26) becomes(27)- selected freestream speed- reference semi-chord- complex response frequency and eigenvalue, , generalized mass, damping, stiffness matrices- generalized aerodynamic matrix- freestream density- reduced frequency,- eigenvector of modal coordinates- damping factor
Dynamic AeroelasticityDynamic AeroelasticityP-K Method Comments Matrices are real but non-symmetric yielding complex roots. Flutter equation only true when , an estimate elsewhere Mode switching often occurs making results interpretation difficult depends on Mach number and reduced frequency Solution requires to be a continuous function of .- Results in curve fitting which can cause errors
Above formulation does not allow User responsible for determining match point solutions
Dynamic AeroelasticityAGARD 445.6 Flutter CalculationsMode Shapes and frequencies
Dynamic AeroelasticityAGARD 445.6 Time Integration Response
Dynamic AeroelasticityAGARD 445.6 Time Response Integration
Dynamic AeroelasticityAGARD 445.6 P-K Flutter Solution
Dynamic AeroelasticityAGARD 445.6 P-K Flutter Solutionradrad
Dynamic AeroelasticityAGARD 445.6 P-K Flutter Solution
Aeroelastic SoftwareGlobal Aeroelastic Software Developments MSC/NASTRAN (U.S.) UAI/ASTROS (recently bought by MSC) (U.S.) UAI/NASTRAN (U.S.) ELFINI (France, Dessault) LAGRANGE (Germany, formerly MBB) STARS (Great Britain, RAE) OPTSYS (Sweden, SAAB) COMPASS (China) ARGON (Russia, Central Aerohydrodynamic Institute)
Aeroelastic SoftwareMSC/NASTRAN Steady Aerodynamics- Subsonic Doublet Lattice (k=0) 3-D panel Method (available in the near future) Bypass option for any AIC- Supersonic ZONA51 Bypass option for any AIC Aerodynamic database Import/export loads data
Unsteady Aerodynamic- Subsonic Doublet Lattice with body interference Strip Theory- Supersonic Mach Box Piston Theory ZONA51
Structural Modeling- Very rich selection of FE
Static Aeroelastic Analysis- 5 DOF trim (no drag/thrust trim)- Flexible increment analysis- Computes rigid, restrained and unrestrained flexible stability derivatives- Able to add experimental load correction factors to AIC- Divergence of restrained vehicle- Slender body models- Multiple set selectable aerodynamic models- Aeroelastic database- Import/export loads data
Dynamic Aeroelasticity- Frequency response analysis- Random analysis- Transient analysis- Gust (random and discrete 1-d)- Flutter P-K, K, K-E (K-E allows k=0)- curve fits cubic through all points
F-S Interface- Infinite plate spline- Thin plate spline- Finite plate spline- Beam spline- Rigid load Transfer
Pre-Post Processing- Extensive Flight Loads pre/post processing functionality in PATRAN environment
Aeroelastic SoftwareUAI/ASTROS Aeroelastic Capabilities Steady Aerodynamics- Subsonic USSAERO (Woodward Aerodynamics, flat panel) QUADPAN (Lockheed Martin, 3-D panel) Bypass option for any AIC Multiple set selectable aerodynamic models- Supersonic USSAERO (flat panel) QUADPAN (3-D panel) Bypass option for any AIC
Unsteady Aerodynamic- Subsonic Doublet Lattice- Supersonic Constant Pressure Method (Apa, Northrop)
Structural Modeling- Membrane type FEM (Rods, Beams, Shear panels, Quadrilateral Plates, Composites)
Static Aeroelastic Analysis- Full 6 DOF Trim- Computes rigid and four types of flexible stability derivatives- User defined loads- Trim Optimization
Dynamic Aeroelasticity- Gust Response- Flutter P-K (computes flutter velocity)- Several choices for curve fits
F-S Interface- Infinite Plate spline- 3-D surface spline- Beam spline- Rigid load Transfer
Very easy to add user defined functionality and tailor the system
Dynamic AeroelasticityDynamic Aeroelasticity(23) can be solved by time integration or as an eigenvalue problem
Aeroelastic SoftwareAeroelastic SoftwareAeroelastic SoftwareAeroelastic Software