AAE 450 Spring 2008

Molly KaneFebruary 14, 2008Structures Group

Analysis of Unpressurized External Structure

AAE 450 Spring 2008

Unpressurized Conical Shells

Structures Group

Nose cone

Third Stage (Pressurized)

Skirt 2 (Unpressurized)

Second Stage (Pressurized)

Skirt 1 (Unpressurized)

Stage 1 (Pressurized)

AAE 450 Spring 2008

Future Work Working with MAT data, affects of stringers and

support rings on critical values

Structures Group

0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04 0.045 0.050

0.5

1

1.5

2

2.5

3

3.5

4

4.5x 10

8 Variations of Skin Thickness

Skin Thickness (m)

Crit

ical

Pre

ssur

e, P

cr (

Pa)

steel

titanium

aluminum

AAE 450 Spring 2008

References Weingarten, V.I., Seide, P., Buckling of Thin-Walled

Truncated Cones – NASA Space Vehicle Design Criteria (Structures), National Aeronautics and Space Administration, September 1968.

Structures Group

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Critical Pressure – Axial Compression

Structures Group

2 2

2

2 cos

3(1 )cr

EtP

= correlation factor to account for difference between classical theory and predicted instability loads

E = Young’s modulus

α = semivertex angle of cone

ν = Poisson’s ratio

t = thickness

Slide by: Jessica Schoenbauer

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Critical Moment - Bending

Structures Group

2 21

2

cos

3(1 )cr

Et rM

= correlation factor to account for difference between classical theory and predicted instability loads

E = Young’s modulus

α = semivertex angle of cone

ν = Poisson’s ratio

t = thicknessr1 = radius of small end of cone

Slide by: Jessica Schoenbauer

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Uniform Hydrostatic Pressure

Pressure:

Structures Group

5

2

0.92cr

Ep

Lt

= correlation factor to account for difference between classical

theory and predicted instability loadsE = Young’s modulust = thicknessL = slant length of conet = thickness

1 2

2cos

r r

Slide by: Jessica Schoenbauer

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Torsion

Structures Group

1 53 2 4

252.8

12(1 )cr

Et t rT

l t

= correlation factor to account for difference between classical theory and predicted instability loads

E = Young’s modulus

ν = Poisson’s ratio

t = thicknessl = axial length of cone

t = thickness1 1

2 22 2 1

21 1 2

1 1cos 1 1 1

2 2

r r rr r

r r r

Slide by: Jessica Schoenbauer