Structures proyect

Box Structure DesignFinal Project

POLITECHNIC UNIVERSITY OF PUERTO RICO

DEPARTMENT OF MECHANICAL ENGINEERING

HATO REY, PUERTO RICO

ME5930: Aerospace StructuresSP-13

Carlos J. Gutiérrez Román #54543

Table of Contents

Executive Summary.....................................................................................................................................2

Introduction.................................................................................................................................................3

Assumptions................................................................................................................................................4

Design Approach- Standards and Considerations........................................................................................5

Calculations and Results..............................................................................................................................6

Final Selection and Recommendations........................................................................................................9

CAD Drawings............................................................................................................................................19

References.................................................................................................................................................21

Appendix...................................................................................................................................................22

Page | 1

Executive Summary

Aircraft wing boxes are a very complex structure because they need to withstand not only the

forces of drag and lift but also its own weight and in most cases the weight of the engines and

the trust these produce. All these forces create a lot of stresses on the wing and each

component job is to withstand a corresponding stress. In this project we are designing a wing

box that has to be able to survive a set of specified constraints. We started by using the

Schrenks span wise load approximations to obtain the shear and bending moments that the

forces produce on each section (rib) across the wing. Then we used these stresses to design the

stringers and the skin of our wing box using the theories and procedures learned in class. Our

design consisted of twelve ribs, two spars and eight stringers. We have to repeat this

procedure for each of the sections we divided the wing span. We used the Von misses and

maximum shear stress theories to calculate the margin of safety associated with each

component to evaluate if our design was successful. In order to facilitate the calculations we

used Microsoft Excel to make the calculations and Solidworks to draw the CAD and obtain

values for area and skin lengths. The result is a very simple but effective wing box that fully

complains with the design specifications.

Page | 2

Introduction

When designing an aircraft many factors contribute to the process. Depending on the type of

aircraft, its shape, mission, performance parameters and weight distribution between others all

the structural requirements change dramatically. Most of the loads that will be acting on the

aircraft produce different stresses that act on different structural elements but all need to be

designed simultaneously. While designing the wing structure the factors are simplified and the

design depends on loads affecting only the wing, which cause shear forces and moments. Using

an industry standard factor of safety we analyzed the acting stresses caused by the loads and

from here on we designed the structure to obtain a positive margin of safety. In this paper the

preliminary design for a wing box structure is explained. The students were given a specific

wing shape with its dimension; also known was the weight of the engines that each wing will

carry and the total weight of the aircraft. With this information we designed the complete wing

box structure and completed a full analysis for each stringer and the skin of the wing.

Page | 3

Assumptions

Weight 145000Nlimit 2.25F.S. 1.5W. Engine 5400W. Span 1344Half Span 672Cr 108Ct 48Ơ7075 73000 psiƠ7178 78000 psi0 00 0

According to the FAA (Federal Aviation Administration) FAR (Federal

Aviation Regulations) a factor of safety of 1.5 must be applied to the limit

load which has external loads on the structure considered.

Limit maneuvering load factors.

(a) Except where limited by maximum (static) lift coefficients, the airplane is assumed to be subjected to

symmetrical maneuvers resulting in the limit maneuvering load factors prescribed in this section.

Pitching velocities appropriate to the corresponding pull-up and steady turn maneuvers must be taken

into account.

(b) The positive limit maneuvering load factor "n" for any speed up to VD may not be less than

2.1+( 24,000W+10,000 )

Page | 4

Design Approach- Standards and Considerations

Airfoil:

NACA0012 – 12.5% from the leading edge and 25% from the trailing edge where eliminated for the wing box design.

Ribs:

Twelve ribs were used with the following areas:

Rib 12.00 11.00 10.00 9.00 8.00 7.00 6.00 5.00 4.00 3.00 2.00 1.00 0.00Area 706.57 927.49 1148.17 1369.09 1589.78 1810.70 2031.38 2252.30 2472.99 2693.91 2914.59 3135.52 3356.20

Stringers:

Eight 672 inch long stringers with an area that varies with its length as follows:

Section 12.00 11.00 10.00 9.00 8.00 7.00 6.00 5.00 4.00 3.00 2.00 1.00Area 12.00 11.00 10.00 9.00 8.00 7.00 6.00 5.00 4.00 3.00 2.00 1.00

Skin and spars:

Skin and rib length are specified according to the rib area. A common thickness of 0.125 inch was used for the skin and 0.5 inch for the spars.

Cross section example of root rib:

All the components were verified for its corresponding bending moment stress or shear stress according to the principles learned in class. Maximum Shear Stress and Von Misses Theories were utilized to calculate the margin of safety.

Page | 5

Calculations and Results

Examples of calculations made by hand:

Schrenks Span Wise Load Approximations

Ultimate Vertical Load

F yaw=12FS (N yW )=1

21.5 (2.25×145,000 )=245,213.7

Wing span lift factor

C l1 ( z )=

12C (Z )+C e ( z )

C (Z )=

12

(48+0 )

48=0.5

Average local lift coefficient

C l1avg i=C l (Z i )+C l (Z i−1 )

2=0.5+1.06

2=0.78

Strip Area

Ai= (Z i−Z i−1 )×C (Z i )+C (Z i−1 )

2=(56 )× 48+63

2=3108¿2

Force Between the Strips

F yawi=2 F yaw

S×C l1avg i Ai=

2×245,213.7185,472

×0.78 (3108 )=6,410.21lb

Distance to Forces

ZFyawi=Z i−( ΔZ i

2 )=672−(562 )=644∈¿

Shear

V z=V z−1−F yawi=−6399−11,378.46=−17,778 lb

Moment

M y=F yawi( ΔZ i

2 )=6,399.18( 562 )=179,177.04 lb .∈¿

Page | 6

Bending Moment stresses

(Station #1, Stringer #3)

Assumptions

Y position=47.45∈¿

Zposition=−13.63∈¿

Area=12¿2

Inertia−Y=12,030.59¿4

Y c position=71.25∈¿

M y=−63,668,511.86 lb−¿

Shear=V z=231,726.40 lb

Dist. To Yc

¿Y position−Y c position=47.45−71.25=−23.80

Bending Stress

¿( M y

Inertia−Y ) (Z position )=(−63,668,511.86 lb12,030.59 ) (−13.63 )=72132.92 psi

Shear Flows and shear stress

(Station #1, Surface 3,4)

Lenght=L=47.55∈¿

Thickness=t=0.125∈¿

TorsionDistance ¿q ' 8=27.26∈¿

Ā=3655.2¿2

Torsion=9,906,303.57 lb .∈¿

Page | 7

q ' 3,4=q '2,3−( V z

Inertia−Y ) ( Area×Z position )=0−( 231,726.4012,030.59 ) (12×−13.63 )=3150.40 lb¿

q 'TorsionMoment=q ' 3,4×TorsionDistance ¿q ' 20×Lenght=3150.40×27.26×47.55=4,083,588.19 lb−¿

q0=∑ q 'TorsionMoment+Torque

2× Ā=

−15220423.02+(−9906303.57)2×3655.2

=−3743.33 lb¿

q=q '+q0=3150.40+(−3743.33 )=−592.93lb−¿

τ=( qThickness )=(−592.930.125 )=−4743.45 psi

Von-Mises

(Station #1, Stringer #3)

σ stringer ¿3¿=72,132.92 psi

σ yieldmaterial=σ 7175=73,000 psi

M .S=σ yieldmaterial

σ stringer

−1= 73,00072,132.92

−1=0.10

Maximum Shear Stress

(Station #1, Skin section 6,7)

τ 6,7=16391.73 psi

σ yieldmaterial=σ 7150=63,000 psi

M .S=σ yieldmaterial x0.577

τ skin section−1=63,000x 0.577

16391.73−1=1.22

Page | 8

Calculations and results obtained using Microsoft Excel

Schrenks Span Wise Load Approximations

Station Zi(in) Czi(in) Cel(in) CL1 (z) CL1avg DZi Ai(in²) FyaWi (lb) ZFyawi (in) Shear (lb) Moment (lb-in)12.00 672.00 48.00 0.00 0.50 0.78 56.00 3108.00 4109.11 644.00 0.00 0.0011.00 616.00 63.00 70.22 1.06 1.09 56.00 3948.00 11037.69 588.00 -4109.11 115054.9810.00 560.00 78.00 97.13 1.12 1.12 56.00 4788.00 14212.68 532.00 -15146.80 654220.319.00 504.00 93.00 116.22 1.12 1.12 56.00 5628.00 16739.38 476.00 -29359.47 1900395.948.00 448.00 108.00 130.96 1.11 1.09 56.00 6468.00 18921.07 420.00 -46098.85 4013229.077.00 392.00 123.00 142.72 1.08 1.07 56.00 7308.00 20872.57 364.00 -65019.92 7124554.686.00 336.00 138.00 152.17 1.05 1.04 56.00 8148.00 22650.93 308.00 -85892.49 11350102.255.00 280.00 153.00 159.73 1.02 1.01 56.00 8988.00 24288.74 252.00 -108543.42 16794307.844.00 224.00 168.00 165.66 0.99 0.98 56.00 9828.00 25806.20 196.00 -132832.16 23552824.153.00 168.00 183.00 170.13 0.96 0.95 56.00 10668.00 14814.74 140.00 -158638.36 31713998.802.00 112.00 198.00 173.25 0.94 0.92 56.00 11508.00 28527.71 84.00 -173453.11 41012559.911.00 56.00 213.00 175.10 0.91 0.90 56.00 12348.00 29745.58 28.00 -201980.82 51524709.790.00 0.00 228.00 175.71 0.89 -231726.40 63668511.86

Total = 231726.40 5.50

Page | 9

Page | 10

Shear and moment diagrams

Page | 11

Bending Moments Stresses and Margin of Safety per station (Aluminum 7075-T6)

Page | 12

Page | 13

Station 1Stringer

1.00 0.00 11.53 12.00 12030.59 71.25 -71.25 -61019.26 0.202.00 0.00 -11.53 12.00 -71.25 61019.26 0.203.00 47.45 -13.63 12.00 -23.80 72132.92 0.014.00 95.05 -11.43 12.00 270858.41 0.00 23.80 60490.04 0.215.00 142.50 -7.21 12.00 71.25 38130.42 0.916.00 142.50 7.21 12.00 71.25 -38130.42 0.917.00 95.05 11.43 12.00 23.80 -60490.04 0.218.00 47.45 13.63 12.00 -23.80 -72132.92 0.01

Total: 96.00

Station 2Stringer

1.00 0.00 10.77 11.00 9625.44 66.57 -66.57 -57661.42 0.272.00 0.00 -10.77 11.00 -66.57 57661.42 0.273.00 44.33 -12.73 11.00 -22.23 68163.50 0.074.00 88.80 -10.68 11.00 216708.48 0.00 22.23 57161.32 0.285.00 133.13 -6.73 11.00 66.57 36032.13 1.036.00 133.13 6.73 11.00 66.57 -36032.13 1.037.00 88.80 10.68 11.00 22.23 -57161.32 0.288.00 44.33 12.73 11.00 -22.23 -68163.50 0.07

Total: 88.00

Station 3Stringer

1.00 0.00 10.01 10.00 7560.78 61.88 -61.88 -54313.78 0.342.00 0.00 -10.01 10.00 -61.88 54313.78 0.343.00 41.21 -11.84 10.00 -20.67 64206.14 0.144.00 82.54 -9.93 10.00 170224.38 0.00 20.67 53842.72 0.365.00 123.75 -6.26 10.00 61.88 33940.22 1.156.00 123.75 6.26 10.00 61.88 -33940.22 1.157.00 82.54 9.93 10.00 20.67 -53842.72 0.368.00 41.21 11.84 10.00 -20.67 -64206.14 0.14

Total: 80.00

Station 4Stringer

1.00 0.00 9.25 9.00 5813.25 57.19 -57.19 -50489.00 0.452.00 0.00 -9.25 9.00 -57.19 50489.00 0.453.00 38.09 -10.94 9.00 -19.10 59684.74 0.224.00 76.29 -9.17 9.00 130880.23 0.00 19.10 50051.11 0.465.00 114.38 -5.78 9.00 57.19 31550.15 1.316.00 114.38 5.78 9.00 57.19 -31550.15 1.317.00 76.29 9.17 9.00 19.10 -50051.11 0.468.00 38.09 10.94 9.00 -19.10 -59684.74 0.22

Total: 72.00

My (lb-in.)-41012559.91

Shear (lb.)173453.11

My (lb-in.)

Dist. to Yc

Dist. to Yc

Dist. to Yc

Intertia - Z (in^4.) Zc position (in.)

-31713998.80Shear (lb.)158638.36

Zc position (in.)



-63668511.86My (lb-in.)

Shear (lb.)231726.40

My (lb-in.)-51524709.79

Shear (lb.)201980.82

Yc position (in.)

Y positoin (in.) Zc position (in.)Area (in².)

Inertia - Y (in^4.) Yc position (in.)

Y position (in.) Zc position (in.) Area (in².) Inertia - Y (in^4.)

Y position (in.) Y position (in.)Area (in².)


Y position (in.) Z position (in.)Area (in².) Inertia - Y (in^4.)

Yc position (in.)

Intertia - Z (in^4.)

Dist. to Yc (in.)Bending Stress

(psi)

Bending Stress (psi)



MS

MS

MS

MS

Page | 14

Station 5Stringer

1.00 0.00 8.50 8.00 4354.56 52.50 -52.50 -45951.75 0.592.00 0.00 -8.50 8.00 -52.50 45951.75 0.593.00 34.97 -10.04 8.00 -17.54 54321.11 0.344.00 70.04 -8.42 8.00 98039.24 0.00 17.54 45553.21 0.605.00 105.00 -5.31 8.00 52.50 28714.86 1.546.00 105.00 5.31 8.00 52.50 -28714.86 1.547.00 70.04 8.42 8.00 17.54 -45553.21 0.608.00 34.97 10.04 8.00 -17.54 -54321.11 0.34

Total: 64.00

Station 6Stringer

1.00 0.00 7.74 7.00 3160.55 47.82 -47.82 -41115.76 0.782.00 0.00 -7.74 7.00 -47.82 41115.76 0.783.00 31.84 -9.15 7.00 -15.97 48604.32 0.504.00 63.79 -7.67 7.00 71157.01 0.00 15.97 40759.16 0.795.00 95.63 -4.84 7.00 47.82 25692.89 1.846.00 95.63 4.84 7.00 47.82 -25692.89 1.847.00 63.79 7.67 7.00 15.97 -40759.16 0.798.00 31.84 9.15 7.00 -15.97 -48604.32 0.50

Total: 56.00

My (lb-in.)-16794307.84

Shear (lb.)108543.42


My (lb-in.)-23552824.15

Shear (lb.)132832.16

Dist. to Yc

Dist. to Yc


Y positoin (in.) Zc position (in.) Area (in².) Inertia - Y (in^4.) Yc position (in.)

Y positoin (in.) Zc position (in.) Area (in².) Inertia - Y (in^4.) Yc position (in.)Bending Stress

(psi)


MS

MS

Station 7Stringer

1.00 0.00 6.98 6.00 2203.66 43.13 -43.13 -35944.11 1.032.00 0.00 -6.98 6.00 -43.13 35944.11 1.033.00 28.72 -8.25 6.00 -14.40 42490.74 0.724.00 57.53 -6.92 6.00 49613.61 0.00 14.40 35632.37 1.055.00 86.25 -4.36 6.00 43.13 22461.17 2.256.00 86.25 4.36 6.00 43.13 -22461.17 2.257.00 57.53 6.92 6.00 14.40 -35632.37 1.058.00 28.72 8.25 6.00 -14.40 -42490.74 0.72

Total: 48.00

Station 8Stringer

1.00 0.00 6.22 5.00 1459.06 38.44 -38.44 -30374.75 1.402.00 0.00 -6.22 5.00 -38.44 30374.75 1.403.00 25.60 -7.35 5.00 -12.84 35907.01 1.034.00 51.28 -6.17 5.00 32849.45 0.00 12.84 30111.31 1.425.00 76.88 -3.89 5.00 38.44 18980.93 2.856.00 76.88 3.89 5.00 38.44 -18980.93 2.857.00 51.28 6.17 5.00 12.84 -30111.31 1.428.00 25.60 7.35 5.00 -12.84 -35907.01 1.03

Total: 40.00


MS

MS

Y position (in.) Zc position (in.) Area (in².)Bending Stress

(psi)

Shear (lb.)65019.92

Dist. to Yc

Dist. to Yc

My (lb-in.)-7124554.68

My (lb-in.)-11350102.25

Shear (lb.)85892.49




Y position (in.) Zc position (in.) Area (in².) Inertia - Y (in^4.) Yc position (in.)

Shear Flows, Shear stresses and Margin of Safety per station (Aluminum 7050-T73511)

Page | 15

Station 9Stringer

1.00 0.00 5.46 4.00 899.80 33.75 -33.75 -24359.51 2.002.00 0.00 -5.46 4.00 -33.75 24359.51 2.003.00 22.48 -6.46 4.00 -11.27 28796.19 1.544.00 45.02 -5.41 4.00 20258.11 0.00 11.27 24148.24 2.025.00 67.50 -3.41 4.00 33.75 15222.05 3.806.00 67.50 3.41 4.00 33.75 -15222.05 3.807.00 45.02 5.41 4.00 11.27 -24148.24 2.028.00 22.48 6.46 4.00 -11.27 -28796.19 1.54

Total: 32.00

Station 10Stringer

1.00 0.00 4.70 3.00 500.49 29.07 -29.07 -17859.15 3.092.00 0.00 -4.70 3.00 -29.07 17859.15 3.093.00 19.36 -5.56 3.00 -9.71 21111.91 2.464.00 38.77 -4.66 3.00 11268.17 0.00 9.71 17704.26 3.125.00 58.13 -2.94 3.00 29.07 11160.04 5.546.00 58.13 2.94 3.00 29.07 -11160.04 5.547.00 38.77 4.66 3.00 9.71 -17704.26 3.128.00 19.36 5.56 3.00 -9.71 -21111.91 2.46

Total: 24.00

Station 11Stringer

1.00 0.00 3.94 2.00 234.67 24.38 -24.38 -10996.58 5.642.00 0.00 -3.94 2.00 -24.38 10996.58 5.643.00 16.23 -4.66 2.00 -8.14 12999.43 4.624.00 32.52 -3.91 2.00 5283.36 0.00 8.14 10901.21 5.705.00 48.75 -2.46 2.00 24.38 6871.67 9.626.00 48.75 2.46 2.00 24.38 -6871.67 9.627.00 32.52 3.91 2.00 8.14 -10901.21 5.708.00 16.23 4.66 2.00 -8.14 -12999.43 4.62

Total: 16.00

Station 12Stringer

1.00 0.00 3.19 1.00 76.56 19.69 -19.69 -4788.15 14.252.00 0.00 -3.19 1.00 -19.69 4788.15 14.253.00 13.11 -3.77 1.00 -6.58 5660.24 11.904.00 26.27 -3.16 1.00 1723.78 0.00 6.58 4746.63 14.385.00 39.38 -1.99 1.00 19.69 2992.08 23.406.00 39.38 1.99 1.00 19.69 -2992.08 23.407.00 26.27 3.16 1.00 6.58 -4746.63 14.388.00 13.11 3.77 1.00 -6.58 -5660.24 11.90

Total: 8.00

MS

MSY position (in.) Zc position (in.)





MS

MS

4109.11

My (lb-in.)-654220.31Shear (lb.)15146.80

Area (in².) Inertia - Y (in^4.) Yc position (in.)

Area (in².)

My (lb-in.)-115054.98Shear (lb.)



Y positoin (in.) Zc position (in.)

Dist. to Yc

Dist. to Yc

Dist. to Yc

Dist. to Yc

My (lb-in.)-1900395.94Shear (lb.)29359.47

My (lb-in.)-4013229.07Shear (lb.)46098.85






Page | 16

Station 1S q' Length Thickness q' distance w/r 8 q' Moments qi= qi ' + qo τ MS

8,1 0.00 47.55 0.13 0.00 0.00 -3743.33 -29946.64 2.211,2 -2665.01 23.05 0.50 2.10 -128999.86 -6408.34 -12816.68 3.842,3 0.00 47.55 0.13 25.16 0.00 -3743.33 -29946.64 2.213,4 3150.40 47.55 0.13 27.26 4083588.19 -592.93 -4743.45 8.664,5 5792.30 47.69 0.13 25.06 6922439.45 2048.97 16391.73 1.225,6 7457.64 14.41 0.50 20.84 2239024.60 3714.31 7428.62 3.896,7 5792.30 47.69 0.13 6.43 1774807.40 2048.97 16391.73 1.227,8 3150.40 47.55 0.13 2.20 329563.24 -592.93 -4743.45 8.66

Total: -15220423.02


8,1 0.00 44.42 0.13 0.00 0.00 -3262.82 -26102.53 2.391,2 -2486.41 21.53 0.50 1.96 -105047.31 -5749.23 -11498.45 4.162,3 0.00 44.42 0.13 23.51 0.00 -3262.82 -26102.53 2.393,4 2939.27 44.42 0.13 25.47 3325351.96 -323.55 -2588.39 15.044,5 5404.11 44.55 0.13 23.41 5637088.41 2141.29 17130.36 1.125,6 6957.85 13.46 0.50 19.47 1823284.94 3695.03 7390.06 3.926,7 5404.11 44.55 0.13 6.00 1445263.09 2141.29 17130.36 1.127,8 2939.27 44.42 0.13 2.06 268370.30 -323.55 -2588.39 15.04

Total: -12394311.40


8,1 0.00 41.29 0.13 0.00 0.00 -2801.98 -22415.82 2.621,2 -2297.08 20.02 0.50 1.82 -83854.46 -5099.05 -10198.11 4.562,3 0.00 41.29 0.13 21.85 0.00 -2801.98 -22415.82 2.623,4 2715.45 41.29 0.13 23.67 2654476.29 -86.53 -692.22 53.514,5 4992.60 41.42 0.13 21.76 4499829.71 2190.63 17525.00 1.075,6 6428.03 12.51 0.50 18.09 1455444.93 3626.05 7252.10 4.016,7 4992.60 41.42 0.13 5.58 1153687.38 2190.63 17525.00 1.077,8 2715.45 41.29 0.13 1.91 214227.73 -86.53 -692.22 53.51

Total: -9893811.59


8,1 0.00 38.17 0.13 0.00 0.00 -2562.66 -20501.27 2.771,2 -2272.98 18.50 0.50 1.69 -70885.46 -4835.64 -9671.29 4.762,3 0.00 38.17 0.13 20.20 0.00 -2562.66 -20501.27 2.773,4 2686.97 38.17 0.13 21.88 2243932.92 124.31 994.50 35.554,5 4940.24 38.28 0.13 20.11 3803882.53 2377.58 19020.67 0.915,6 6360.61 11.57 0.50 16.72 1230344.68 3797.95 7595.90 3.796,7 4940.24 38.28 0.13 5.16 975257.19 2377.58 19020.67 0.917,8 2686.97 38.17 0.13 1.77 181095.10 124.31 994.50 35.55

Total: -8363626.96


8,1 0.00 35.04 0.13 0.00 0.00 -2145.78 -17166.26 3.121,2 -2073.25 16.98 0.50 1.55 -54486.81 -4219.04 -8438.07 5.312,3 0.00 35.04 0.13 18.54 0.00 -2145.78 -17166.26 3.123,4 2450.86 35.04 0.13 20.09 1724821.27 305.08 2440.63 13.894,5 4506.13 35.14 0.13 18.47 2923892.00 2360.35 18882.80 0.935,6 5801.69 10.62 0.50 15.35 945716.636,7 4506.13 35.14 0.13 4.73 749641.117,8 2450.86 35.04 0.13 1.62 139200.54

Total: -6428784.74

Station 6

8,1 0.00 31.911,2 -1860.15 15.472,3 0.00 31.91 0.13 16.88 0.003,4 2198.94 31.91 0.13 18.29 1283657.684,5 4042.96 32.00 0.13 16.82 2176037.875,6 5205.35 9.67 0.50 13.98 703827.376,7 4042.96 32.00 0.13 4.31 557902.777,8 2198.94 31.91 0.13 1.48 103596.73

Total: -4784471.89

Station 7

8,11,22,33,44,55,66,77,8

Total: -3414685.07

Station 8

8,11,22,33,44,55,66,77,8

Total: -2304072.58

Page | 17


8,1 0.00 35.04 0.13 0.00 0.00 -2145.78 -17166.26 3.121,2 -2073.25 16.98 0.50 1.55 -54486.81 -4219.04 -8438.07 5.312,3 0.00 35.04 0.13 18.54 0.00 -2145.78 -17166.26 3.123,4 2450.86 35.04 0.13 20.09 1724821.27 305.08 2440.63 13.894,5 4506.13 35.14 0.13 18.47 2923892.00 2360.35 18882.80 0.935,6 5801.69 10.62 0.50 15.35 945716.636,7 4506.13 35.14 0.13 4.73 749641.117,8 2450.86 35.04 0.13 1.62 139200.54

Total: -6428784.74

Station 6

8,1 0.00 31.911,2 -1860.15 15.472,3 0.00 31.91 0.13 16.88 0.003,4 2198.94 31.91 0.13 18.29 1283657.684,5 4042.96 32.00 0.13 16.82 2176037.875,6 5205.35 9.67 0.50 13.98 703827.376,7 4042.96 32.00 0.13 4.31 557902.777,8 2198.94 31.91 0.13 1.48 103596.73

Total: -4784471.89

Station 7

8,11,22,33,44,55,66,77,8

Total: -3414685.07

Station 8

8,11,22,33,44,55,66,77,8

Total: -2304072.58


8,1 0.00 22.52 0.13 0.00 0.00 -744.69 -5957.48 7.101,2 -1119.24 10.92 0.50 0.99 -12156.06 -1863.93 -3727.86 10.752,3 0.00 22.52 0.13 11.92 0.00 -744.69 -5957.48 7.103,4 1323.10 22.52 0.13 12.91 384809.19 578.41 4627.28 6.864,5 2432.63 22.59 0.13 11.87 652322.96 1687.95 13503.58 1.695,6 3132.04 6.83 0.50 9.87 210990.24 2387.35 4774.71 6.616,77,8

Total: -1434267.70

Station 10

8,11,22,33,44,55,66,77,8

Total: -786656.17

Station 11

8,11,22,33,44,55,66,77,8

Total: -340354.73

Station 12

8,11,22,33,44,55,66,77,8

Total: -74586.37

Final Selection and RecommendationsMaterial for stringers:

Page | 18


8,1 0.00 22.52 0.13 0.00 0.00 -744.69 -5957.48 7.101,2 -1119.24 10.92 0.50 0.99 -12156.06 -1863.93 -3727.86 10.752,3 0.00 22.52 0.13 11.92 0.00 -744.69 -5957.48 7.103,4 1323.10 22.52 0.13 12.91 384809.19 578.41 4627.28 6.864,5 2432.63 22.59 0.13 11.87 652322.96 1687.95 13503.58 1.695,6 3132.04 6.83 0.50 9.87 210990.24 2387.35 4774.71 6.616,77,8

Total: -1434267.70

Station 10

8,11,22,33,44,55,66,77,8

Total: -786656.17

Station 11

8,11,22,33,44,55,66,77,8

Total: -340354.73

Station 12

8,11,22,33,44,55,66,77,8

Total: -74586.37

Material for skin:

All the stringers and skin sections meet the desired requirements and obtain a Margin of safety greater

than 0.

Page | 19

Our design consists of 12 rib sections with 8 stringers running across the wing. To minimize overdesign

we choose a variable area stringer design. All the sections consist of the same layout reduced in size by

a factor given on the following table. All the corresponding dimensions and coordinates for all the 12

ribs, spars and stringers are also found in the table.

CAD Drawings

Page | 20

% from 12 Station Length Spar 0 Y Spar 1 Y Spar 2 Y Spar 4 Y Upper Arc Lower Arc 0.21 12.00 30.00 0.00 9.99 20.01 30.00 30.07 30.070.28 11.00 39.38 0.00 13.11 26.27 39.38 39.47 39.470.34 10.00 48.75 0.00 16.23 32.52 48.75 48.86 48.860.41 9.00 58.13 0.00 19.36 38.77 58.13 58.26 58.260.47 8.00 67.50 0.00 22.48 45.02 67.50 67.66 67.660.54 7.00 76.88 0.00 25.60 51.28 76.88 77.05 77.050.61 6.00 86.25 0.00 28.72 57.53 86.25 86.45 86.450.67 5.00 95.63 0.00 31.84 63.79 95.63 95.85 95.850.74 4.00 105.00 0.00 34.97 70.04 105.00 105.25 105.250.80 3.00 114.38 0.00 38.09 76.29 114.38 114.64 114.640.87 2.00 123.75 0.00 41.21 82.54 123.75 124.04 124.040.93 1.00 133.13 0.00 44.33 88.80 133.13 133.44 133.441.00 0.00 142.50 0.00 47.45 95.05 142.50 142.83 142.83

References

Shigley’s Mechanical Engineering Design 9th Ed. (Budynas, Nisbett, 2010)

Page | 21

Aluminum (“Aerospace Materials”, 2013)

Preparation of Stress Analysis Report (David McMahon, 2009)

Mechanics of Aircrafts Structures (Sun, 2006)

Aircraft Structures (Peery, 2011)

Appendix

Page | 22

Solidworks Model

Page | 23

Education

Structures proyect