Tutorial: Bending stresses
Q1 The beam shown is subjected to a
bending moment of 40kNm. Determine the
bending stress acting at A and B.
IT  15,104166 x106 m4
 A  198.7 MN / m2 ;  B  66.2MN / m2
Q2 (a) Calculate the maximum bending stress induced in a shaft of diameter
18mm which subjected to be bending moment of 200Nm. [   350 MN / m 2 ]
(b) Determine the diameter of shaft necessary to support a bending moment
of 200Nm so that the stress is not to exceed 200MN/m2.
[ D  21.7mm ]
Q3 A simply supported beam has the cross section
shown opposite. Determine the maximum bending
stress in the beam if simply supported over a span of
6 metres and carrying a uniformly distributed load of
5kN/m.
[ M  22.5kNm , I  3.013x104 m 4 ,   12.69MN / m 2 ]
Q4 (Bd421)The beam section opposite is subjected
to a bending moment of 40kNm.
Determine the maximum tensile and compressive
stresses in the material.
Yfrom.base  144mm ; I  141x106 m4
 top  34.58MN / m2 ;  bottom  40.88MN / m 2
Q5 The diagram shown represents the cross
section of a beam. Determine:
the second moment of area without the hole.
the second moment of area with the hole.
I without  28.1x106 mm 4
I with  26.4 x106 mm4 ;
NA  71.24mm from.bot
Q6 A beam of width 80mm and depth 120mm is made of steel
(   7800kg / m2 ) and a 5m section is simply supported over as span of 5m
determine the value and nature of the maximum stress induced in the beam
2
due to its own weight.
[ w  734.6 N / m , M  2296Nm ,   11.96 MN / m ]