Unformatted text preview: the minimum fillet radius needed at the
junction between the two portions of the shaft.
The maximum shearing stress in the portion of the shaft with the 2in.
diameter: Thus, the minimum permissible
radius for the fillet between the
two portions of the shaft is: K.M. Anwar Hossain, PhD, PEng;
Ryerson University Class problem
695: A fillet with a radius of 1/8 in. is used at the
junction in a stepped shaft where the diameter is
reduced from 8 inch to 6 inch. Determine the
maximum torque that the shaft can transmit if
the maximum shearing stress in the fillet must
be limited to 12 ksi.
696: A semicircular groove with a 5mm radius is
required in a 110mm diameter shaft. If the
maximum shearing stress in the shaft must be
limited to 60 MPa, determine the maximun
torque that can be transmitted by the shaft.
K.M. Anwar Hossain, PhD, PEng;
Ryerson University K.M. Anwar Hossain, PhD, PEng;
Ryerson University 5 Torsion in Noncircular Section
Torsional stresses are proportional to distance from the axis. If
this is true the torsional stresses should be higher at the
corner of the rectangular crosssection
Duleau (1820) proved that this is not true for rectangular
section. K.M. Anwar Hossain, PhD, PEng;
Ryerson University If there is stress at the corners , it could be
resolved into two components: orthogonal stresses
would also exist as shown by dashed arrows K.M. Anwar Hossain, PhD, PEng;
Ryerson University K.M. Anwar Hossain, PhD, PEng;
Ryerson University Last
components
can not
exist
because of
the free
surface
Therefore,
shearing
stress at the
corner
should be
zero 6 • First correct analysis of
torsional behaviour of
noncircular section was
published by “Saint
Venant in 1855
• It shows that except for
circular crosssection,
every section will warp
(not remain in plane)
when twisted.
• For rectangular section,
the distortion of the small
squares is maximum at
the midpoint of a side of
the crosssection and
disappears at the corner Torsion in Noncircular Section K.M. Anwar Hossain, P...
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 Spring '14
 Civil Engineering, Force, Shear Stress, Stress concentration, K.M. Anwar Hossain

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