Activity 2
Mechanics of Materials
Name: _________________________________________________________ ID: ________________
1. In the figure is shown a portion of the landing gear of a plane. Determine the compression stress
in the damper AB produced by a reaction to the landing spot of 20 KN, AB forms an angle of
53.1° with BC. The damper AB has a tubular cross section with inner diameter of 30 mm and
outer diameter of 40 mm.
FIME-UANL
1
Activity 2
Mechanics of Materials
Name: _________________________________________________________ ID: ________________
2. The link BD consists on a unique bar with 30mm of width and 12 mm of thickness. Knowing
that every bolt has a diameter of 10 mm, calculate the maximum value of the normal average
stress in link BD if:
a. θ = 0 º.
b. θ = 90 º.
FIME-UANL
2
Activity 2
Mechanics of Materials
Name: _________________________________________________________ ID: ________________
3. All the bars of the structure have a cross-section area of 1.25in2. Determine the normal stress on
each bar if the load P is 8 kips. Mention if the stress is of tension or compression.
FIME-UANL
3
Activity 2
Mechanics of Materials
Name: _________________________________________________________ ID: ________________
4. Calculate the compressive stress in the connecting rod when a force P = 10pounds is applied to
the brake pedal (notices that the attachment line of the force P is parallel to the connecting rod).
The diameter of the connecting rod is of 0.22 in and the other showed dimensions are
perpendiculars to the action line of the force P.
FIME-UANL
4
Activity 2
Mechanics of Materials
Name: _________________________________________________________ ID: ________________
5. A column, in a two-floor construction, is manufactured with structural square pipe, with the
cross dimensions that are shown in the figure. The column supports the axial loads PA and PB
as indicated. Calculate the axial stress in the segment AB and in the segment BC. (Do not
consider the weight of the column).
FIME-UANL
5
Activity 2
Mechanics of Materials
Name: _________________________________________________________ ID: ________________
6. The leaned lever represented in the image is in equilibrium:
a. Find the diameter of the AB bar if the normal stress is limited to 100 MPa.
b. Find the shear stress in the pin placed in D, with 20 mm of diameter.
FIME-UANL
6
Activity 2
Mechanics of Materials
Name: _________________________________________________________ ID: ________________
7. A hydraulic punch with a capacity of 500 kN makes round holes on an aluminum plate of 10
mm of thickness. If the shear stress resistance of this plate is of 250 MPa. What is the maximum
diameter of the hole that can be punched?
FIME-UANL
7
Activity 2
Mechanics of Materials
Name: _________________________________________________________ ID: ________________
8. Two bars of rectangular cross sections, thickness t of 5/16 in, are joined by a bolt as shown in
the figure, the permissible shear stress in the bolt is of 12,000 psi and the permissible bearing
stress between bolt and bars is 20,000 psi. If the force of tension P is 1,800 lbs. What is the
minimum necessary diameter of the pin?
FIME-UANL
8
Activity 2
Mechanics of Materials
Name: _________________________________________________________ ID: ________________
9. Three pieces of wood are joined with bolts, to make a column. The diameter of each bolt is ½ in
and the inner diameter of each washer is 5/8 in, the diameter of the washer is a little bigger than
the diameter of the hole in the wood. Determine the minimum outer diameter in the washers,
knowing that the limit normal stress in the bolts is 5 ksi and the bearing stress between the
washers and the wood cannot exceed 1.2 ksi.
FIME-UANL
9
Activity 2
Mechanics of Materials
Name: _________________________________________________________ ID: ________________
10. The post of oak (60 x 60 mm) is supported by the block of pine, if the permissible bearing stress
for these materials is 43 MPa and 25 MPa respectively, determine the maximum load that they
can support. If a stiff plate is placed between the two materials, determine its required area so
that the maximum load can be borne, what value has this load?
FIME-UANL
10