HW#3
Read/Study:


Chapter-3 Load and Stress Analysis
o Curved beams in bending 3-18 (skip alternative calculation for e)
o Contact stresses 3-19
o Summary 3-20
Chapter-4 Deflection and Stiffness
o Spring rate 4-1
o Tension, compression, torsion 4-2
o Strain Energy 4-7
o Castigliano’s theorem 4-8
Problem #1
Given




A disk made of class 30 grey cast iron (Table A-24).
ID = 1 inch
OD = 12 inches
Thickness = 1 inch
Shatters when tangential stress reaches Sut = 31000 psi.
Find

The rpm for which the disk tangential stress in the inner radius (r=0.5 inch) reaches the
ultimate stress.
Problem #2
Give




A steel pulley hub press fitted on a solid steel shaft
Shaft diameter = 50.025 mm
Hub diameter = 50.000 mm
Hub OD is = 100 mm
Find
a) Interface Pressure in MPa
b) Tangential stress for the hub at r=25 mm in MPa
c) Radial stress for the hub at r=25 mm in MPa
Problem #3 – Create a professional-looking presentation for the solution (typed text, equations,
graphics and graphs) – You can use MS Word and Excel, MathCad, or any other program that allows
professional-looking presentations
Given




A steel hook with rectangular cross-section supporting 10000 lbs
Inner radius = 2 inches
Outer radius = 4 inches
Thickness = 1 inch
Find
a) Maximum bending tensile stress in psi at the inner radius using curved beam formula
b) A graph shown the bending stress as the inner radius changes from 2 inches to 20 inches. The
outer radius is always 2 inches more than the inner radius.
1 inch
10000 lbs