Page 167 - Shigley's Mechanical Engineering Design

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142 Mechanical Engineering Design
thread body. Using the given coordinate system label the stresses using the notation given
in Fig. 3–8a.
(d) A square-thread power screw has an outside diameter d = 1.5 in, pitch p = 0.25 in, and
transmits a load F = 1 500 lbf through the application of a torque T = 235 lbf · in. If n t = 2,
determine the key stresses and the corresponding principal stresses (normal and shear).
3–91 Develop the formulas for the maximum radial and tangential stresses in a thick-walled cylinder
due to internal pressure only.
3–92 Repeat Prob. 3–91 where the cylinder is subject to external pressure only. At what radii do the
maximum stresses occur?
3–93 Develop the equations for the principal stresses in a thin-walled spherical pressure vessel of
inside diameter d i, thickness t, and with an internal pressure p i. You may wish to follow a process
similar to that used for a thin-walled cylindrical pressure vessel on p. 114.
3–94 to A pressure cylinder has an outer diameter d o , wall thickness t, internal pressure p i , and maximum
3–96 allowable shear stress τ max . In the table given, determine the appropriate value of x.

Problem
Number d o t p i max
3–94 6 in 0.25 in x max 10 kpsi
3–95 200 mm x min 4 MPa 25 MPa
3–96 8 in 0.25 in 500 psi x

3–97 to A pressure cylinder has an outer diameter d o, wall thickness t, external pressure p o, and maximum
3–99 allowable shear stress τ max . In the table given, determine the appropriate value of x.

Problem
Number d o t p o max
3–97 6 in 0.25 in x max 10 kpsi
3–98 200 mm x min 4 MPa 25 MPa
3–99 8 in 0.25 in 500 psi x

3–100 An AISI 1040 cold-drawn steel tube has an OD = 50 mm and wall thickness 6 mm. What max-
imum external pressure can this tube withstand if the largest principal normal stress is not to
exceed 80 percent of the minimum yield strength of the material?
3–101 Repeat Prob. 3–100 with an OD of 2 in and wall thickness of 0.25 in.
3–102 Repeat Prob. 3–100 with an internal pressure.
3–103 Repeat Prob. 3–101 with an internal pressure.
3–104 A thin-walled cylindrical steel water storage tank 30 ft in diameter and 60 ft long is oriented with
its longitudinal axis vertical. The tank is topped with a hemispherical steel dome. The wall thick-
ness of the tank and dome is 0.75 in. If the tank is unpressurized and contains water 55 ft above
its base, and considering the weight of the tank, determine the maximum state of stress in the
tank and the corresponding principal stresses (normal and shear). The weight density of water
3
is 62.4 lbf/ft .