instructions
Instructions
Enter your name and student numbe
(note pay particular attention to your student number as this is used to generate solutions for marking your values)
Enter your results in the yellow cells provided in the "solutions" tab. Do not move the location of any of the yellow cells
Use exact values where possible in calculation, and enter exact values in cells.
It is recommended to use Microsoft Excel (or some other spreadsheet software) to process the calculation component of the results.
Results are marked co
ect if within 5% tolerance of exact answer.
Submit solutions online using Canvas - file is uploaded where this template file was downloaded from
Each time a submission is uploaded this is an "attempt". Each attempt should have 1 file: this spreadsheet
Multiple submission attempts are possible, but only the LAST submission attempt is marked
Email or hard copy submission will not be accepted
&"Cali
i"&12&KEEDC00RMIT Classification: Trusted&1#
solutions
name
student #
Refer to the assignment for more detailed
description of the parameters to be entered
1 Question 1 (40%)
a) Stiffener axial loads (lbf): Use positive for tension and negative for compression
Segment (Seg) and location (Loc), e.g. AB A is the force in stiffener segment AB at location A
Seg Loc
AB A
B
BC B
C
AF A
F
BD B
D
CE C
E
DE D
E
DG D
G
EH E
H
FG F
G
GH G
H
Shear flows (lbf/in). Only absolute values marked (signs ignored)
Panel and edge, e.g. ABGF AB is panel ABGF, edge AB
ABGF AB
BG
GF
FA
BCED BC
CE
ED
DB
DEHG DE
EH
HG
GD
(b) Stiffener areas (in2), for each segment
AB
BC
AF
BD
CE
DE
DG
EH
FG
GH
Shear panel thicknesses (in) for each panel
ABGF
BCED
DEHG
2 Question 2 (60%)
a) Shear flows (N/mm). Only absolute values marked (signs ignored)
Panel, e.g. 1-2 is the panel between stiffeners 1 and 2
1-2
1-3
3-1 curved
3-4
2-5
2-4
5-4
Criitical margin of safety (MoS)
MoS
b) Resized panel thicknesses (mm)
Panel, e.g. 1-2 is the panel between stiffeners 1 and 2
1-2
1-3
3-1 curved
3-4
2-5
2-4
5-4
Question 2a consequential marks
Provide intermediate results to assist with awarding consequential marks
Maximum of marks from either final values or consequential marks taken
Panel, e.g. 1-2 is the panel between stiffeners 1 and 2, with positive direction from 1-2
"basic" Shear flows (N/mm), q
1-2
1-3
3-1 curved
3-4
2-5
2-4
5-4
matrix terms A, B and x that could be used to solve for unknowns x using [A]{x} = [B], with qc positive clockwise and qb positive as stated above
A11
A12
A13
A14
A21
A22
A23
A24
A31
A32
A33
A34
A41
A42
A43
A44
B11
B21
B31
B41
x11
x21
x31
x41
Margin of Safety (MoS) in shea
1-2
1-3
3-1 curved
3-4
2-5
2-4
5-4
&"Cali
i"&12&KEEDC00RMIT Classification: Trusted&1#
Microsoft Word - AERO2359-2110_assignment-2.docx
Page 1 of 3
Aerospace Structures
Assignment 2: Stiffened Structures
Individual assignment: One per student. Multiple attempts allowed, but only last submission graded.
Ensure you review your file after submission and avoid leaving submission until the last minute.
Marks awarded for ANSWERS only.
Use solutions template to enter in results and follow instructions provided in template file.
Question 0: Your student number is used to assign parameters, according to the table below.
Digit 3rd 4th 5th 6th 7th
Parameter a b A B C D E F
Value
XXXXXXXXXX XXXXXXXXXX
XXXXXXXXXX XXXXXXXXXX
XXXXXXXXXX XXXXXXXXXX
XXXXXXXXXX XXXXXXXXXX
XXXXXXXXXX XXXXXXXXXX
XXXXXXXXXX XXXXXXXXXX
XXXXXXXXXX XXXXXXXXXX
XXXXXXXXXX XXXXXXXXXX
XXXXXXXXXX XXXXXXXXXX
XXXXXXXXXX XXXXXXXXXX
e.g.: Student number XXXXXXXXXX, produces the following table of values
Digit 3rd 4th 5th 6th 7th
Parameter a b A B C D E F
Value XXXXXXXXXX
XXXXXXXXXX XXXXXXXXXX
Scott Loh
Highlight
Scott Loh
Highlight
Scott Loh
Highlight
Scott Loh
Highlight
Page 2 of 3
Question 1 (40%)
The tapered stiffened beam below is loaded by forces as shown. The beam is assumed to
consist of stiffeners ca
ying only direct stress and shear panels ca
ying only shear stress. The
material used has E = 10500 ksi, G = 3900 ksi, ty = 48 ksi,cy = 38 ksi, sy = 37 ksi. The values
of a, b, A, C, E are taken from Question 0.
(a) Calculate the stiffener axial loads (lbf) at the end of each beam segment and the shea
flows (lbf/in) along each panel edge. (30%)
(b) Size the beam by determining stiffener areas (in2) and shear panel thicknesses (in). (10%)
For stiffeners, size to yield stress (in tension or compression), considering the maximum
load in each segment (i.e. each segment can have a different area). For the shear panels,
size to yield stress (in shear, maximum in each panel) or shear buckling, whichever is
critical. For the buckling calculation, assume that the shear panels are simply supported on
all edges, and for the tapered panels use the smaller edge dimensions (i.e. assume a
ectangular panel with the smaller of the width and height edge dimensions). When sizing,
use a minimum possible area of 0.30 in2 and a minimum possible thickness of XXXXXXXXXXin.
A B
F
G
C
H
D E
dimensions
in inches
S1
5.0
5a
6.0
S3
2.5
6a
S2
y
x
S1 = A kip
S2 = C kip
S3 = E kip
2
Page 3 of 3
Question 2 (60%)
The three-cell structure shown below uses stiffeners connected with shear panels. Note that the
curved panel between stiffeners 1 and 3 is semi-circular. The structure is under the action of
forces and moments as shown. Assume the shear panels do not ca
y any direct stress. The
material properties are: E = 72 GPa, G = 28 GPa, ty = 270 MPa,
cy = 240 MPa, y = 170 MPa. The values of a, b, B, D, F are taken from Question 0.
(a) Calculate the shear flow (N/mm) in each panel and determine the critical margin of safety
in shear (not buckling or any other mode). (50%)
(b) Re-size the thickness (mm) of the shear panels to reduce the cross-sectional area to
achieve the following design requirements (10%):
1. area fraction A/A0 less than 0.30
2. all margins of safety greater than or equal to 0.0
3. no panel thickness less than XXXXXXXXXXmm
The area fraction is calculated as A/A0, where A is the cross-sectional area of all panels
combined, and A0 is the cross-sectional area of all panels using thicknesses as shown in
the figure below.
In re-sizing the panels, you should consider that the beam cross-section dimensions and
stiffener areas are fixed, and that only the panel thicknesses can be varied. You should
only consider failure due to shear (not buckling or any other mode).
dimensions in mm
areas in mm2
Booms 2, 4, 5: area = 50b
panel thickness (t)
t = 1.5 mm for all panels except
t1-3 = 5 mm
y
x
Booms 1, 3: XXXXXXXXXXarea = 700a
L = B kN
D = D kN
MAC = F kN m
0.5D
0.5D
MAC
1
4
2
3
1500
I II III
750
5
200
0.3L
MTE
MTE = 0.2F kN m
0.7L