19

0800CET201122003

Module 5

A rectangular element ABCD of an elastic material is subjected to a shear stress
of 17.5 MPa. The planes at right angles carry tensile stress of 70 MPa and
compressive stress of 35 MPa respectively.
Determine:

i) The magnitude of the principal stresses.

ii) The direction of the principal planes.

iii) The magnitude of maximum shear stress.

iv) The orientation of the plane of maximum shear stress.

wl as

17.5MPa

ത്ത്‌ B
‏لصي‎ i
↞−−−−−−− >

101/೧3
11.51/0
D ட
‏سج‎ 39
Figure 7

20.a A short column having a length of 0.5 m and made of solid aluminium rod of

25mm diameter is pinned at both the ends. Determine the Euler’s critical load
for the column. If in order to reduce the weight of the member by 25%, the
cross section is changed to hollow circular section of 25 mm external diameter,
determine the critical load of the modified column. Also determine the
percentage reduction in critical load due to cross section modification. Take E =
72.8 GPa.

A hollow circular shaft of 30 mm outer radius transmits a power of 180 kW
while rotating at a frequency of 25 Hertz. Find the thickness of the circular shaft

if the allowable shear stress is 60MPa.

मर KK ‏بد‎

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