Engineering Mechanics assignment

Project description
Dont forget to draw free body diagrams when calculating forces and moments.
Dont forget to label lengths and angles when doing geometric calculations.
Dont forget to include your axes and units when plotting graphs.
Show all steps in your solution and state your assumptions, it is better to include an
extra step than not.
Marks will be deducted for sloppy solutions and diagrams!

1
ENS1101 €“ Engineering Mechanics
Assignment
Lecturer: Dr Shuo LI
Instructions:
?
Students need to work in groups of
2 to 3
and submit one assignment per group.
?
Students need to attach a cover sheet with
the names and IDs of each participant.
?
Do not use plastic folders, simply stapl
e the top left corner of your assignment.
?
Submit the assignment to
the engineering front offi
ce in building 23 by
31/10/2014, 3
pm,
penalties will apply to late submissions
. Do not email me the assignment!
?
Don’t forget to draw free body diagram
s when calculating forces and moments.
?
Don’t forget to label lengths and angl
es when doing geometric calculations.
?
Don’t forget to include your ax
es and units when plotting graphs.
?
Show all steps in your solution and state yo
ur assumptions, it is better to include an
extra step than not.
?
Marks will be deducted for sloppy solutions and diagrams!
?
This assignment will contribute to 15%
of the overall mark for the unit.
Good luck!
2
1.
The ramp shown below is used to a
ssist passengers boarding light commuter
aircrafts. The average mass of the ramp
and passengers is 800 kg with the center of
mass located at point
G
. As the ramp angle
?
increases, the hydraulic cylinder
extends but the distance bet
ween the center of mass
G
and pivot
C
remains fixed.
(10 points)
a) Derive the equation for length
AB
as a function of
BC, AC
and
?
. (1 points)
b) Derive the equation for angle
BAC
as a function of
BC, AB
and
?
. (2 points
c) Calculate the pivot reaction force (
F
C
) and hydraulic cylinder force (
F
AB
) at a
ramp angle of 10 degrees. (4 points)
d) Plot the variation of
Fc
and
F
AB
as a function of
?
over the range 10 <
?
< 20.
(3 points)
3
2.
Consider the plane truss shown below. The reaction force at points A and B act at
an angle of
a
= 30 and
ß
= 22 degrees relative to t
he horizontal axis. (10 points)
a) Determine the reaction forces at points
A
and
B
. (2 points)
b) Determine the force in member
AH
. (1 marks)
c) Determine the force in members
BH
and
BC
. (3 points)
d) Determine the force in members
CH
and
HG
. (2 points)
e) Determine the force in members
CD
and
CG
. (2 points)
4
3.
The pipe clamp ends are designed to fi
t a standard 20 mm steel water pipe. The
right hand fitting can slide along the pipe when handle
C
is held up to release its grip
on the pipe. When the handle is released
and a clamping load of F = 1000 N is
applied by the screw, the fitting make
s contact with the pipe at points
A
and
B
. In this
position, the spring is compressed with a sp
ring constant of 400 N/mm. Assume that
the handle is a frictionle
ss surface.(10 points)
a) Determine the static fric
tion coefficient at point
B
needed to avoid slip under
loading. (2 points)
b) Calculate the force acting at point
A
and
B
under loading. (2 points)
c) Estimate the compression of the sp
ring under loading. Assume that the
handle
OC
remains parallel to the pipe. (3 points)
d) Calculate the handle force required
to loosen the fitting. (2 points)
e) Calculate the force supported by pin
O
when the above handle force is
applied. (1 points)
End of assignment