MED360S 2025
Chapter 1. Tutorials
1. Design a solid shaft for a 15 hp motor operating at a speed N.
Given: G=80 GPa, Sys=150 MPa, N= 2500 rpm. The angle of twist is limited to 2° per
meter length.
Design Assumptions: The shaft is made of steel. A factor of safety of 3 is used
(Ref. P9.1) Ans. D = 20 mm
2. A 40 hp motor, through a set of gears, drives a shaft at a speed n, as shown in Figure
below
a. Based on a safety factor of 2, design solid shafts AC and BC.
b. Determine the total angle of twist between A and B.
Given: G=82 GPa, Sys=210 MPa, n =1200 rpm.
(Ref. P9.3) Ans. (a) DAC = 14.25 mm ; DCB = 20.56 mm/ (b) ∅𝐴𝐵 = 7.93𝑜
3. A solid steel shaft carries belt tensions (at an angle α from the y axis in the yz plane)
at pulley C, as shown in Figure here below. For α= 0 and a factor of safety of n, design
the shaft according to the following failure criteria:
a. Maximum shear stress.
b. Maximum energy of distortion.
Given: Sy=250 MPa, n=1.5. (Ref. P9.7) Ans. (a) D = 42.71 mm/ (b) D = 42.3 mm
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Chapter 1. Tutorials
1. Design a solid shaft for a 15 hp motor operating at a speed N.
Given: G=80 GPa, Sys=150 MPa, N= 2500 rpm. The angle of twist is limited to 2° per
meter length.
Design Assumptions: The shaft is made of steel. A factor of safety of 3 is used
(Ref. P9.1) Ans. D = 20 mm
2. A 40 hp motor, through a set of gears, drives a shaft at a speed n, as shown in Figure
below
a. Based on a safety factor of 2, design solid shafts AC and BC.
b. Determine the total angle of twist between A and B.
Given: G=82 GPa, Sys=210 MPa, n =1200 rpm.
(Ref. P9.3) Ans. (a) DAC = 14.25 mm ; DCB = 20.56 mm/ (b) ∅𝐴𝐵 = 7.93𝑜
3. A solid steel shaft carries belt tensions (at an angle α from the y axis in the yz plane)
at pulley C, as shown in Figure here below. For α= 0 and a factor of safety of n, design
the shaft according to the following failure criteria:
a. Maximum shear stress.
b. Maximum energy of distortion.
Given: Sy=250 MPa, n=1.5. (Ref. P9.7) Ans. (a) D = 42.71 mm/ (b) D = 42.3 mm
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