1

Q.THE rotating solid steel shaft is simply supported by bearings at point B and C

and is to transmit a torque of 1000 lb-in to point A.the force F acts on the gear at

point D at a pressure angle of 20* from the horizontal.the gear has 4-inch diameter

and the shaft has 3/8 inch diameter

A.Determine the force

B.find support reactions at B and C and draw SFD and BMD diagrams of the shaft

in both horizontal and vertical planes.

C.Find the critical point of the shaft and determine its stresses.

Solution:

=

2

= 1000

= = 4

= 20

1000

4

=

2

2

A.

=

=

. & .

Shear Moment Diagram:

Bending Moment diagram

+ = 532

3

1000 = 1000 + 532 14

= 844.80

+ = 532

= 532 844.80 = 312.80 ()

C:Critical point :the point on shaft where bending moment is largest.

= = .

& = 4

= 532 4 = 2128

The maximum bending moment will be at point c

Due to roatation the bending is completely reversed while torque/torsion is constant

= = 2128

4