The frame is an integral structural part of an automobile. It supports power plant , transmission system, wheels and tyres etc. The body is also fitted on it. Attachment of all these parts and systems may be rigid or flexible. The front and rear wheels are connected with the frame by means of spring shackles. Frames are supported by a suspension system which is attached to the wheels. This is done for comfortable driving.

1. FRAMES AND BODY
Prepared by:
Sagar Joshi

2. FRAME
 The frame is an integral structural part of an
automobile.
 It supports power plant , transmission system,
wheels and tyres etc.
 The body is also fitted on it.
 Attachment of all these parts and systems may be
rigid or flexible.

3. FRAME
 The front and rear wheels are connected with the
frame by means of spring shackles.
 Frames are supported by a suspension system
which is attached to the wheels.
 This is done for comfortable driving.

4. FRAME

5. FUNCTIONS OF FRAMES
1. To carry load of the passengers or goods carried in
the body.
2. To support the load of the body, engine, gear box
etc.,
3. To withstand the forces caused due to the sudden
braking or acceleration
4. To withstand the stresses caused due to the bad
road condition.
5. To withstand centrifugal force while cornering

6. FRAMES
 The frames consists of various members placed in
different orientation and different locations. They
are as below
a) Longitudinal side member
b) Front member
c) Rear member
d) Intermediate member
e) Diagonal member

7. FRAMES
 The longitudinal member extends length wise from
front to rear.
 Cross members are placed transversly along with
width.
 Diagonal memmber has cross orientation.

8. LOADS ON THE FRAMES
 Flexural (Bending) Load:
It is produced in a vertical plane of the side
member.
It is due to the
• Dead weight of the vehicle
• Weight of the passenger
• Engine Torque
• Braking Torque

9. LOADS ON THE FRAMES
 Flexural (Bending) Load:
The effect of flexural load is to cause the flexural
stresses which can be either tensile or compressive
in nature.
The compressive stresses are resisted by placing
thrust taking members between the frame and back
axle.
The tensile stresses are resisted by using material
of sufficient strength.

10. LOADS ON THE FRAMES
 Torsional Load (Twisting Moment):
It is caused due to vertical load when the vehicle
comes across a road bump.
The twisting induces shear stress in the frame.
The frame is designed to strong enough to resist
torsion by providing diagonal member and cross
member.

11. LOADS ON THE FRAMES
 Impact load:
It is caused due to impact of the wheels with road
obstacles.
It may result in distortion of the frame.
Bumpers and over riders are used to sustain
impact loads.
It provides safety and longer life to the frame.

12. CROSS-SECTIONS OF FRAME MEMBERS
 Channel section (in ladder type trucks)
 good to resist bending.
 Used as side members
 Box section (Swaraj Mazda)
 Capable of resisting high twisting.
 Popular in MCV.

13. CROSS-SECTIONS OF FRAME MEMBERS
 I section (Heavy loaded carriers)
 Best to resist bending load.
 Popular in big trucks.
 It is costlier than Channel section.
 Tubular section
 Common on two wheelers.
o Rectangular section
 Resist flexural load effectively.

14. TYPES OF FRAMES
There are three types of frames
1. Conventional frame
2. Integral frame
3. Semi-integral frame

15. TYPES OF FRAMES
1. Conventional frame:
o It has two long side members and 5 to 6 cross
members joined together with the help of rivets and
bolts.
o The frame sections are used generally.
a. Channel Section - Good resistance to bending
b. Tabular Section - Good resistance to Torsion
c. Box Section - Good resistance to both bending
and torsion

16. TYPES OF FRAMES
2. Integral Frame:
o This frame is used now a days in most of the cars.
o There is no frame and all the assembly units are
attached to the body.
o All the functions of the frame carried out by the
body itself.
o Due to elimination of long frame it is cheaper and
due to less weight most economical also.
o Only disadvantage is repairing is difficult.

17. TYPES OF FRAMES
3. Semi - Integral Frame:
o In some vehicles half frame is fixed in the front end
on which engine gear box and front suspension is
mounted.
o It has the advantage when the vehicle is met with
accident the front frame can betaken easily to
replace the damaged chassis frame.

18. BODY
 It can be classified in to two main groups.
a) Passenger body
b) Commercial body
 It can also classified according to Chassis design
the body can divided into
 1. Conventional Type
 2. Integral Type
 3. Semi- Integral Type

19. BODY
 It can also classified according to other usage:
1. Light vehicle Bodies - cars, jeeps
2. Heavy vehicle Bodies – Busses, Lorries
3. Medium vehicle Bodies - Vans, Metadoors

20. BODY

21. BODY

22. REQUIREMENTS OF BODY
 Strength
 Stiffness
 Torsional stiffness
 Space
 Air drag
 Protection against weather
 Lightness
 Resistance to corrosion
 Protection in accident

23. REQUIREMENTS OF BODY
 The body of the most vehicle should fulfill the
following requirements:
1. The body should be light.
2. It should have minimum number of components.
3. It should provide sufficient space for passengers
and luggage.
4. It should withstand vibrations while in motion.
5. It should offer minimum resistance to air.

24. REQUIREMENTS OF BODY
6. It should be cheap and easy in manufacturing.
7. It should be attractive in shape and colour.
8. It should have uniformly distributed load.
9. It should have long fatigue life
10.It should provide good vision and ventilation.

25. BODY

26. DEFECTS IN BODY
 Disturbed alignment in horizontal and/or vertical
plane
 Twisted main frame and/or its sub frame like cross
member
 Buckled main frame and/or its sub frame like cross
member
 Bent side members
 Broken or loose rivets

27. DEFECTS
 If the damage is not substantial, the frames can be
repaired by straightening them.
 Hydraulic jacks, pressure pumps, straightening bar
are used for that.
 They are generally heated before straightening
them.
 Some times the heavily damaged portion is
removed and new part is welded there.

28. AERODYNAMIC CONSIDERATION
 Aerodynamics is the study of forces and the
resulting motion of objects through the air.

29. AERODYNAMIC CONSIDERATION
 Force acting on an object in motion through a fluid
(in this case air) in an opposite direction to the
objects motion, produced by friction.
 Drag is of two types.
a) Pressure drag force FDp
b) Friction drag force FDf
FD = FDp + FDf

30. AERODYNAMIC CONSIDERATION

31. AERODYNAMIC CONSIDERATION

32. AERODYNAMIC CONSIDERATION

33. AERODYNAMIC CONSIDERATION

34. SPOILER