Courses

# PPT: Bending Stresses in Beams Mechanical Engineering Notes | EduRev

## Mechanical Engineering : PPT: Bending Stresses in Beams Mechanical Engineering Notes | EduRev

``` Page 1

4.1 SIMPLE BENDING OR PURE
BENDING
? When some external force acts on a beam, the
shear force and bending moments are set up at
all the sections of the beam
? Due to shear force and bending moment, the
beam undergoes deformation. The material of the
beam offers resistance to deformation
? Stresses introduced by bending moment are
known as bending stresses
? Bending stresses are indirect normal stresses
Page 2

4.1 SIMPLE BENDING OR PURE
BENDING
? When some external force acts on a beam, the
shear force and bending moments are set up at
all the sections of the beam
? Due to shear force and bending moment, the
beam undergoes deformation. The material of the
beam offers resistance to deformation
? Stresses introduced by bending moment are
known as bending stresses
? Bending stresses are indirect normal stresses
4.1 SIMPLE BENDING OR PURE
BENDING
? When a length of a beam is subjected to zero
shear force and constant bending moment, then
that length of beam is subjected to pure bending
or simple pending.
? The stress set up in that length of the beam due
to pure bending is called simple bending stresses
Page 3

4.1 SIMPLE BENDING OR PURE
BENDING
? When some external force acts on a beam, the
shear force and bending moments are set up at
all the sections of the beam
? Due to shear force and bending moment, the
beam undergoes deformation. The material of the
beam offers resistance to deformation
? Stresses introduced by bending moment are
known as bending stresses
? Bending stresses are indirect normal stresses
4.1 SIMPLE BENDING OR PURE
BENDING
? When a length of a beam is subjected to zero
shear force and constant bending moment, then
that length of beam is subjected to pure bending
or simple pending.
? The stress set up in that length of the beam due
to pure bending is called simple bending stresses
4.1 SIMPLE BENDING OR PURE
BENDING
? Consider a simply supported beam with over
hanging portions of equal lengths. Suppose the
beam is subjected to equal loads of intensity W at
either ends of the over hanging portion
? In the portion of beam of length l, the beam is
subjected to constant bending moment of
intensity w x a and shear force in this portion is
zero
? Hence the portion AB is said to be subjected to
pure bending or simple bending
Page 4

4.1 SIMPLE BENDING OR PURE
BENDING
? When some external force acts on a beam, the
shear force and bending moments are set up at
all the sections of the beam
? Due to shear force and bending moment, the
beam undergoes deformation. The material of the
beam offers resistance to deformation
? Stresses introduced by bending moment are
known as bending stresses
? Bending stresses are indirect normal stresses
4.1 SIMPLE BENDING OR PURE
BENDING
? When a length of a beam is subjected to zero
shear force and constant bending moment, then
that length of beam is subjected to pure bending
or simple pending.
? The stress set up in that length of the beam due
to pure bending is called simple bending stresses
4.1 SIMPLE BENDING OR PURE
BENDING
? Consider a simply supported beam with over
hanging portions of equal lengths. Suppose the
beam is subjected to equal loads of intensity W at
either ends of the over hanging portion
? In the portion of beam of length l, the beam is
subjected to constant bending moment of
intensity w x a and shear force in this portion is
zero
? Hence the portion AB is said to be subjected to
pure bending or simple bending
4.2 ASSUMPTIONS FOR THE
THEORY OF PURE BENDING
? The material of the beam is isotropic and
homogeneous. Ie of same density and elastic
properties throughout
? The beam is initially straight and unstressed and
all the longitudinal filaments bend into a circular
arc with a common  centre of curvature
? The elastic limit is nowhere exceeded during the
bending
? Young's modulus for the material is the same in
tension and compression
Page 5

4.1 SIMPLE BENDING OR PURE
BENDING
? When some external force acts on a beam, the
shear force and bending moments are set up at
all the sections of the beam
? Due to shear force and bending moment, the
beam undergoes deformation. The material of the
beam offers resistance to deformation
? Stresses introduced by bending moment are
known as bending stresses
? Bending stresses are indirect normal stresses
4.1 SIMPLE BENDING OR PURE
BENDING
? When a length of a beam is subjected to zero
shear force and constant bending moment, then
that length of beam is subjected to pure bending
or simple pending.
? The stress set up in that length of the beam due
to pure bending is called simple bending stresses
4.1 SIMPLE BENDING OR PURE
BENDING
? Consider a simply supported beam with over
hanging portions of equal lengths. Suppose the
beam is subjected to equal loads of intensity W at
either ends of the over hanging portion
? In the portion of beam of length l, the beam is
subjected to constant bending moment of
intensity w x a and shear force in this portion is
zero
? Hence the portion AB is said to be subjected to
pure bending or simple bending
4.2 ASSUMPTIONS FOR THE
THEORY OF PURE BENDING
? The material of the beam is isotropic and
homogeneous. Ie of same density and elastic
properties throughout
? The beam is initially straight and unstressed and
all the longitudinal filaments bend into a circular
arc with a common  centre of curvature
? The elastic limit is nowhere exceeded during the
bending
? Young's modulus for the material is the same in
tension and compression
4.2 ASSUMPTIONS FOR THE
THEORY OF PURE BENDING
? The transverse sections which were plane before
bending remain plane after bending also
? Radius of curvature is large compared to the
dimensions of the cross section of the beam
? There is no resultant force perpendicular to any
cross section
? All the layers of the beam are free to elongate
and contract, independently of the layer, above or
below it.
```
Offer running on EduRev: Apply code STAYHOME200 to get INR 200 off on our premium plan EduRev Infinity!

## Strength of Materials (SOM)

35 videos|33 docs|48 tests

,

,

,

,

,

,

,

,

,

,

,

,

,

,

,

,

,

,

,

,

,

;