This preview shows pages 1–5. Sign up to view the full content.
1.
Project description
The project consists of four phases. In each phase you perform a portion of the whole analysis
and present your results in report. You will be handing in 4 separate reports, one for each phase.
2.
The Givens
The following design parameters and modeling information are known.
Design Parameters for Aircraft
Gross Weight of Airplane,
W
g
lb 350000+1000*
F
gforce (without gust loads)
#
2.5
Safety factor
#
1.5
Type of Al alloy
#
Al 2024
Young’s modulus,
E
ksi
10,600
Yield strength
ksi
50
The variable
F
involved in the calculation of gross weight is the first digit of your UFID.
Design Parameters for Wingbox
Wingbox Span
in
1490+10*
L
Wingbox root section width, C
WBroot
in
170
Wingbox root section height
in
49
Wingbox root section thickness
in
1
Wingbox tip section width, C
WBtip
in
20
Wingbox tip section height
in
10
Wingbox tip section thickness
in
0.05
Sweep angle,
∆
degrees
30
The variable
L
involved in the calculation of span is the last digit of your UFID.
Design Parameters for Wing (Gust load case)
Wingroot chord,
C
root
in
337.25
Wingtip chord,
C
tip
in
90
Aspect Ratio,
A
r
#
9.3
Wing Gross Area,
S
sq ft
3129
Wing Sweep angle
degrees
30
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document Fig.1
The red lines shows the sweep of the wingbox section which you analyze
Fig.2
Wingbox 3D model
20”
Fig.3
Wingbox top view
Fig.4
Wingbox root section view
170”
745”
(Half
‐
span)
170”
49”
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document Phase 4
Determination of the Crack tip Stress Intensity Factor and Wingtip Deflection
Report: 3 to 4 pages
Due: 12/15/2010
Description
:
Perform a crack tip analysis under the shear stresses and flexural stresses found in the previous
phase to find the crack tip stress intensity factor. It is also very important to keep track of the
wingtip deflection. The following steps would be useful to solve this phase of the project:
(a)
Both flexural stress as well as shear stress has to be taken into account. These values have
to be found for the bottom flange. Assume the shear stress value to be the one at the
center of the bottom flange for the entire crack.
(b)
Now stress transformation has to be done to align the stresses along the coordinate
system of the crack (see figure 5). This will give the necessary stresses to find the stress
intensity factor for different modes.
(c)
To find the wingtip deflection consider the equation
2
2
ell
d
ME
I
dy
where,
is the
deflection along the span and y is along the span. M
ell
is the equation of moment for
elliptic lift in terms of y. The moment of inertia in this equation is also a function y as it
keeps on changing along the span. Consider the wing to be a cantilever beam to decide
the boundary conditions.
Here are the items required in this phase of the project:
1.
A 1.5 in long through thickness crack has been discovered on the bottom surface of the
wing close to the fuselage as shown in the figure below. The crack makes a 45
o
angle
with the yaxis of the wing (along the span). Determine the stress intensity factor K
I
for
Mode I loading. If the fracture toughness of the alloy used is
IC
K
=
2
4
M
P
am , would
you recommend grounding the airplane?
This is the end of the preview. Sign up
to
access the rest of the document.
This note was uploaded on 06/06/2011 for the course EAS 4200C taught by Professor Kim during the Fall '09 term at University of Florida.
 Fall '09
 Kim

Click to edit the document details