Mechanics of Materials Chapters 5 and 6 12/28/2009 by Shun

Mechanics of Materials
Chapters 5 and 6
12/28/2009 by Shun-Fa Hwang 1/3
A steel tube having an outer diameter of 2.5 in. is used to transmit 350 hp when
turning at 27 rev/min. Determine the inner diameter d of the tube to the nearest
1/8 in. if the allowable shear stress is  allow  10 ksi. (1 hp=550 ft•lb/s)[15%]
The two solid steel shafts shown are coupled together using the meshed gears.
Determine the angle of twist of end A of shaft AB when the torque T=45 N•m is
applied. Take G=80 GPa. Shaft AB is free to rotate within bearings E and F,
whereas shaft DC is fixed at D. Each shaft has a diameter of 20 mm. [20%]
The shaft is made from a solid steel section AB and a tubular portion made of
steel and having a brass core. If it is fixed to a rigid support at A, and a torque of
T= 50 lb•ft is applied to it at C, Determine the angle of twist that occurs at C and
compute the maximum shear stress and maxiumu shear strain in the brass and
steel. Take Gst  11.5(103 ) ksi, Gbr  5.6(103 ) ksi. [15%]
Draw the shear and moment diagrams for the beam. [15%]
The aluminum machine part is subjected to a moment of M=75 N•m. (a)
Determine the bending stress created at points B and C on the cross section. (b)
Determine the maximum tensile and compressive bending stress in the part.
The beam has the rectangular cross section shown. If P=12kN, determine the
absolute maximum bending stress in the beam. [15%]