final wing design
TRANSCRIPT
M E 6 3 0 0 : A E R O S P A C E S T R U C T U R E S G A B R I E L H E R E D I A A C E V E D O
J O N A T H A N H O L G U I N O B O R D A
FINAL WING DESIGN
Picture Reference: http://www.cessna.com/~/media/Images/Aircraft/citation/mustang/gallery/exterior/img-
gallery-must-2.ashx
AGENDA
Problem presentation and purpose.
Proposed solutions.
Pugh’s decision matrix.
Design parameters and materials.
Initial load summary (proposed solutions).
Detailed design summary (prevailing model).
Conclusions, additional comments, and references.
PROBLEM PRESENTATION
Design wing structure for an 8,000lb aircraft with 20ft wingspan.
Must conform to FAR23-Subpart C Loading Conditions.
Cruise speed 285mph.
Diving speed 399mph.
Picture Reference:
http://www.darcorp.com/img/far23_leftbar.png
Picture Reference: http://www.charterjets.com/_images/aircraft/citation_
x_750_exterior.jpg
MODEL PROPOSALS
Three Cell Web-Stringer
Picture Reference: AutoCAD Civil 3D Educational
Version Drawing
Picture Reference: AutoCAD Civil 3D Educational
Version Drawing
Two Cell Web-Stringer
Truss Model
Picture Reference: AutoCAD Civil 3D Educational
Version Drawing
PUGH’S DECISION MATRIX
Pro
ble
m S
tate
me
nt
Structures Design of wing type Airfoil - NACA 0012
We
igh
tin
g
Alte
rna
tive
s
Two
Ce
ll W
eb
-Str
ing
er
Thre
e C
ell W
eb
-Str
ing
er
Tru
ss S
tyle
Fra
me
Crite
ria
Weight 25 1 0 -1
Stiffness 15 -1 0 1
Mechanical Resistance 20 0 1 -1
Manufacturability 15 1 0 -1
Maintenance 10 1 0 -1
Cost 15 1 0 -1
Total: 100 50 20 -70
*Green denotes controlling design
DESIGN PROCESS
Design Parameters
Shear Flow Analysis
Principal Stringer
Analysis
Rivet Spacing
Fatigue Analysis Crippling Analysis Aero-elasticity
Analysis
Final Design
Buckling Analysis
DESIGN PARAMETERS & MATERIAL PROPERTIES
NACA-0012 Airfoil profile.
Picture Reference:
http://www.pointwise.com/theconnector
/July-2012/SAE-Fig1-Airfoils-2400x1800.png
Dimensions.
Picture Reference: “Aircraft Wing Load
Analysis Proyecto Final.xlsx”
Trapezoidal Wing Platform
Cr 102 in
Ct 63.75 in
b/2 240 in
Aircraft-Air Interaction Data
Wing-Tail Distance 200 in
Air Density 0.002377 slugs/ft3
Aircraft Weight 8,000 lbs
Cruising Speed 285 mph
Diving Speed 399 mph
*Data Reference: Design Requirements
Aluminum 7075-T6
σYield
(psi) σUltimate
(psi) τYield
(psi) γ
(lb/in3)** ν **
C (Fatigue Constant)
N (Fatigue Constant)
67,000 76,000 33,500 0.1 0.33 2.13E-13 3.21
Aluminum 2024-T3
σYield
(psi) σUltimate
(psi) τYield (psi)
E (ksi) **
G (ksi) **
C (Fatigue Constant)
N (Fatigue Constant)
42,100 63,800 21,050 10,400 4,000 3.22E-14 3.38
Material Properties References: www.matweb.com, “Effect of Stress Ratio on Fatigue-Crack Growth in 7075-T6 and 2024-T3
Aluminum-Alloy Specimens” (Michael Hudson, NASA Technical Note August 1969)
** E, G, γ, and ν are virtually the same for both materials.
WING APPLIED LOADS
*Graphs Reference: “Aircraft Wing Load Analysis Proyecto Final.xlsx”
(“Wing Load Distribution” Sheet)
Loads obtained using Schrenck’s Approximation method and FAR-23 Subpart C.
890
1,229 1,405
1,544 1,660
1,759 1,845
1,920 1,985 2,042 2,090 2,131
0
500
1,000
1,500
2,000
2,500
1 2 3 4 5 6 7 8 9 10 11 12
Str
ip L
oa
d (
lbf)
Wing Station (strip)
Vertical Wing Load
0.50
0.82
0.92
0.98 1.01
1.04 1.05 1.06 1.06 1.05 1.04 1.03 1.02
0.40
0.50
0.60
0.70
0.80
0.90
1.00
1.10
0 20 40 60 80 100 120 140 160 180 200 220 240
Sh
ren
k's
Win
g-S
pa
n L
ift
Fa
cto
r
(cl1
i)
Wing Coordinate (in)
Shrenk's Lift Factor
WING INTERNAL LOADS
2,170,482
1,781,814
1,435,361
1,130,232
865,373
639,564
451,400 299,269
181,321 95,406 38,984 8,899 0
Mz = 44.05291760x2 - 19,442.43869525x +
2,151,888.56198930
R² = 0.99967998
0
500,000
1,000,000
1,500,000
2,000,000
2,500,000
0 20 40 60 80 100 120 140 160 180 200 220 240
Mo
me
nt
(lb
f-in
)
Wing Coordinate (in)
Moment Diagram
0 -890
-2,118 -3,524
-5,068 -6,727
-8,486
-10,331
-12,250
-14,236
-16,277
-18,368
-20,499
V = -0.1212x2 + 116.22x - 20658
-25,000
-20,000
-15,000
-10,000
-5,000
0
0 20 40 60 80 100 120 140 160 180 200 220 240
Sh
ea
r Fo
rce
(lb
f)
Wing Coordinate (in)
Shear Force Diagram
*Graphs Reference: “Aircraft Wing Load Analysis Proyecto Final.xlsx”
(“Wing Load Distribution” Sheet)
Loads obtained using Schrenck’s Approximation method and FAR-23 Subpart C.
TWO-CELL STRUCTURAL BOX
Picture Reference: AutoCAD Civil 3D Educational
Version Drawing
TYPICAL CROSS-SECTIONS
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Version Drawing
WINGWARD PROFILE
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Version Drawing
WINGWARD ORTHOGONAL VIEW
Picture Reference: AutoCAD Civil 3D Educational
Version Drawing
MARGINS OF SAFETY (AXIAL STRESS)
Stringer σz (psi) M.S. Yield
Aluminum
7075-T6
M.S. Yield
Aluminum
2024-T3
M.S. Ultimate
Aluminum
7075-T6
M.S. Ultimate
Aluminum
2024-T3
1 63,568.56 36.75% -0.66% 16.36% 0.36%
2 -63,568.56 36.75% -0.66% 16.36% 0.36%
3 -61,602.67 38.70% 2.45% 18.94% 3.44%
4 -39,944.95 60.25% 36.75% 47.44% 37.39%
5 39,944.95 60.25% 36.75% 47.44% 37.39%
6 61,602.67 38.70% 2.45% 18.94% 3.44%
*Table Reference: “Aircraft Wing Load Analysis Proyecto Final.xlsx”
(“Summary” Sheet)
*Green denotes controlling margin of safety for this criterion
MARGINS OF SAFETY (SHEAR FLOW)
*Table Reference: “Aircraft Wing Load Analysis Proyecto Final.xlsx”
(“Summary” Sheet)
*Green denotes controlling margin of safety for this criterion
Element τxy (psi) M.S. Shear Aluminum
7075-T6 M.S. Shear
Aluminum 2024-T3
12(1) -3,205.85 83.42% 73.62%
12(2) -12,230.96 36.76% -0.64%
23 -3,039.50 84.28% 74.99%
34 3,371.64 82.57% 72.26%
45 16,256.78 15.95% -33.77%
56 3,371.64 82.57% 72.26%
61 -3,039.50 84.28% 74.99%
MARGINS OF SAFETY (BUCKLING)
*Table Reference: “Aircraft Wing Load Analysis Proyecto Final.xlsx”
(“Summary” Sheet)
*Green denotes controlling margin of safety for this criterion
Stringer σz (psi) M.S. Buckling Element M.S. Buckling Skin
1 63,568.56 17.09% 12(1) 90.11%
2 -63,568.56 17.09% 23 91.27%
3 -61,602.67 81.66% 34 91.27%
4 -39,944.95 18.80% 56 89.02%
5 39,944.95 18.80% 61 89.02%
6 61,602.67 81.66%
MARGINS OF SAFETY (FATIGUE & AERO-ELASTICITY)
*Tables Reference: “Aircraft Wing Load Analysis Proyecto Final.xlsx”
(“Summary” Sheet)
*Green denotes controlling margin of safety for this criterion
Element M.S. Fatigue Skin
23 27.13%
34 0.51%
Aero-elasticity M.S. Diverging
Speed
Wing 98.74%
SECTION SUMMARY
Section Additional Comments
Principal Stringers
1, 2 L2.5X2X5/16 Aluminum 7075-T6
3, 6 3x1.5x5/16 Aluminum 7075-T6
4, 5 L1.5x1.5x5/16 Aluminum 7075-T6
Secondary Stringers
Segment 12(1) 7.45% chord spacing Custom Aluminum 7075-T6 Section
Segment 16 4.10% chord spacing Custom Aluminum 7075-T6 Section
Segment 45 4.10% chord spacing Custom Aluminum 7075-T6 Section
Segment 23 5.00% chord spacing Custom Aluminum 7075-T6 Section
Segment 34 5.00% chord spacing Custom Aluminum 7075-T6 Section
Skin Design
Segment 12(1) 0.09 in Aluminum 7075-T6
Segment 12(2) 0.04 in Aluminum 7075-T6
Segment 23 0.08 in Aluminum 2024-T3
Segment 34 0.08 in Aluminum 2024-T3
Segment 45 0.0275 in Aluminum 7075-T6
Segment 56 0.08 in Aluminum 7075-T6
Segment 16 0.08 in Aluminum 7075-T6
Rivet Spacing 1.5 in Universal Head
Fatigue Design
Segment 23 8928 cycles to recommended change (3:1 Safety Factor)
Aluminum 2024-T3, based on edge crack behavior
Segment 34 6852 cycles to recommended change (3:1 Safety Factor)
Aluminum 2024-T3, based on edge crack behavior
*Tables Reference: “Aircraft Wing Load Analysis Proyecto Final.xlsx” (“Design Summary Section Details” Sheet)
CONCLUSION
Final wing weight estimated at 288 lb.
The design complies with all design considerations.
The design complies to Federal requirements as in
FAR 23 Subpart C.
RECOMMENDATIONS
Consider including flaps and aileron analysis for
future revision.
Material reduction for rib analysis.
Design wing using Finite Element Analysis and
comparison with analytical solution.
Use of composite material for future revision.
Flutter analysis for future revision.
BIBLIOGRAPHY
“ADVANCED MECHANICS OF MATERIALS AND APPLIED ELASTICITY ,“ Fifth Edition 2012, Ansel C. Ugural & Saul K. Fenster
“Aerodynamics Aeronautics and Flight Mechanics,” Second Edition 1995, Mc CORMICK
“Publications in Areonautical Science,” 1956, Khun
“THE SCIENCE AND ENGINEERING OF MATERIALS,” Fifth Edition 2008, Askeland & Phulé
“Conocimientos del AVION,” 2004, Antonio Oñate
“Theory of Wing Sections,” 1959, Abott & Von Doenhoff
“Weight-Strength Analysis of Aircraft Structures,” Second Edition 1960, Shanley
“Aircraft Structures,” 2011, D. J. Peery
“Steel Construction Manual,” Thirteenth Edition 2006, A.I.S.C.
“Aircraft Design A Conceptual Approach,” Fifth Edition 2012, D. P. Raymer
“AIRFRAME STRESS ANALYSIS AND SIZING,” Third Edition 2011, M. C. Niu
“Effect of Stress Ratio on Fatigue-Crack Growth in 7075-T6 and 2024-T3 Aluminum-Alloy Specimens,” 1969, NASA Technical Note Michael Hudson
eCFR-Code of Federal Regulations Volume 14 – FAR 23 Subpart C, 2013, FAA
Aerospace Structures ME 6300 Course Material, 2014, Dr. Hector Rodríguez