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Part # 001: Ceiling Bracket
| Images | Calculations |
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 | Material: Carbon steel
E = 202,700 N/mm2
Yield strength = 220 Mpa
Loads
P/2 = 111.2 N
P/4 = 55.6 N
(P = 50 lbs)
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 | Bending along X-axis
Distance between support forces: 200 mm
Vertical centroid: -7.57 mm (measure from top surface)
Second moment of area about centroidal axis: 3510 mm4
Maximum bending moment: 5,560 N*mm2
Maximum x-bending stress: 9.47 N/mm2 = 9.47 Mpa
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 | Bending along Z-axis
Distance between support forces: 70 mm
Vertical centroid: -.66 mm (measure from top surface)
Second moment of area about centroidal axis: 37.8 mm4
Maximum bending moment: 1,946 N*mm2
Maximum z-bending stress: 3.4 N/mm2 = 3.4 Mpa
Maximum net bending stress: 10.1 Mpa
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Stress Concentration Factor
h = 1.22 mm (sheet thickness)
w = 50 mm (section width)
d = 6 mm (hole size)
d/w = .12 d/h = 5
K = 1.7 - From table A-15-12 of (Shigley, Mechanical Engineering Design)
Actual Maximum Stress = 17.1 Mpa
Safety Factor = 12.9 Mpa
Part # 002: U-Pulley Mount
| Images | Calculations |
|
 | Material: Carbon steel
E = 202,700 N/mm2
Yield strength = 220 Mpa
Loads
P/2 = 111.2 N
P/4 = 55.6 N
(P = 50 lbs)
|
 | Bending along X-axis
Distance between support forces: 20 mm
Vertical centroid: -.66 mm (measure from top surface)
Second moment of area about centroidal axis: 3.03 mm4
Maximum bending moment: 556 N*mm2
Maximum x-bending stress: 12.1 N/mm2 = 12.1 Mpa
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 | Stress Concentration Factor
h = 1.22 mm (sheet thickness)
w = 48 mm (section width)
d = 6 mm (hole size)
d/w = .13 d/h = 5
K = 1.7 - From table A-15-12 of (Shigley, Mechanical Engineering Design)
Actual Maximum Stress = 20.6 Mpa
Safety Factor = 10.7 Mpa
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Part # 003: Pulley Wheel
| Images | Calculations |
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 | Material: Injection molded plastic
E = 3,500 N/mm2
v = .4
Yield strength = 103 Mpa
Loads
P/2 = 111.2 N
Ft = force resulting from tension in rope
(P = 50 lbs)
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 | Contact Stress
Diameter 1: 5.3 mm
Diameter 2: 4.9 mm
Contact length = 13.5mm
Half-width of contact surface = 2 mm
Maximum Compressive Stress = 4.2 Mpa
Safety Factor = 24.5
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Part # 004: Pulley Rivet
| Images | Calculations |
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 | Material: Aluminum
E = 69,000 N/mm2
Yield strength = 95 Mpa
Loads
P/2 = 111.2 N
P/4 = 55.6 N
(P = 50 lbs)
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 | Shear Stress
Diameter: 4.9 mm
Length = 20 mm
Maximum shear force = 55.6 N
Shear area = 18.9 mm2
Maximum Compressive Stress = 2.9 Mpa
Safety Factor = 32.3
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Part # 001: V-Bracket
| Images | Calculations |
|
 | Material: Carbon steel
E = 202,700 N/mm2
Yield strength = 220 Mpa
Loads
P/2 = 111.2 N
P/4 = 55.6 N
Mz = 1780 N*mm
(P = 50 lbs)
|
 | Bending along X-axis
Distance between support forces: 200 mm
Vertical centroid: -7.57 mm (measure from top surface)
Second moment of area about centroidal axis: 3510 mm4
Maximum bending moment: 5,560 N*mm2
Maximum x-bending stress: 9.47 N/mm2 = 9.47 Mpa
|
 | Bending along Z-axis
Distance between support forces: 70 mm
Vertical centroid: -.66 mm (measure from top surface)
Second moment of area about centroidal axis: 37.8 mm4
Maximum bending moment: 1,946 N*mm2
Maximum z-bending stress: 3.4 N/mm2 = 3.4 Mpa
Maximum net bending stress: 10.1 Mpa
|
Stress Concentration Factor
h = 1.22 mm (sheet thickness)
w = 50 mm (section width)
d = 6 mm (hole size)
d/w = .12 d/h = 5
K = 1.7 - From table A-15-12 of (Shigley, Mechanical Engineering Design)
Actual Maximum Stress = 17.1 Mpa
Safety Factor = 12.9 Mpa
