The presentation includes the chassis classification, BAJA Vehicle Chassis Design & its analysis.

2. CATIA INTRODUCTION
 CATIA (Computer Aided Three-dimensioning Interactive
Application) is a computer aided design tool programmed in
C++ language by Dassault Systems and marketed by IBM.
 CATIA is the world’s leading CAD/CAM/CAE software.
 It is also called as 3D ‘Product Lifecycle Management’ software
because it is also used at various industrial levels from design
process to manufacturing level of various products.
 CATIA offers a solution to shape design, styling, surfacing
workflow and visualization to create modify, and validate
complex innovative shapes .

3. BAJA
 Baja SAE is an intercollegiate design competition run by
the Society of Automotive Engineers (SAE).
 The goal in Baja SAE racing is to design, build and race
off-road vehicles.
 Baja is sponsored by “Mahindra & Mahindra Limited”.

4. CHASSIS
 Roll Cage can be called as skeleton of a vehicle, its main
purpose is to form a frame or so called Chassis.
Types of Chassis
 LADDER FRAME CHASSIS
 TUBULAR SPACE FRAME CHASSIS
 MONOCOQUE FRAME CHASSIS
 ULSAB MONOCOQUE
 BACKBONE FRAME CHASSIS
 ALUMINIUM SPACE FRAME
 CARBON-FIBBER MONOCOQUE

5.  LADDER FRAME CHASSIS
Advantages-
The following are the advantages -
 it is easy
 cheap for hand build
 Proves good for SUVs.

6. Disadvantages-
 Torsional rigidity is very much lower especially when dealing
with vertical load or bumps.
Who use it ?
It is used by Most SUVs, classic cars, Lincoln Town Car, Ford,
Crown Victoria etc.
 TUBULAR SPACE FRAME CHASSIS

7.  3 dimensional design
 high-end sports cars adopt tubular space frame to enhance the
rigidity / weight ratio
 tubes are welded together and forms a very complex structure
Advantages-
 Very strong in any direction. (compare with ladder chassis and
monocoque chassis of the same weight)
Disadvantages-
 Very complex.
 Costly and time consuming to be built.
 Impossible for robotised production.
 Besides, it engages a lot of space,
 Raise the door sill and result in difficult access to the cabin.

8. Who use it ?
It was used by all Ferrari before the 360M, Lamborghini Diablo,
Jaguar XJ220, Cater ham, TVR etc.
 MONOCOQUE FRAME CHASSIS
 Monocoque is a one-piece structure which defines the overall
shape of the car.
 The floor pan, which is the largest piece, and other pieces are
press-made by big stamping machines.

9.  Chassis is actually made by spot welding several pieces
together.
Advantages-
 Cheap for mass production.
 Inherently good crash protection.
 Space efficient.
Disadvantages-
 Heavy.
 Impossible for small-volume production.
Who use it ?
 Nearly all mass production cars, all current Porsche

10.  ULSAB MONOCOQUE
 Ultra Light Steel Auto Body (ULSAB)
 It has the same structure as a conventional monocoque
 It differs from its donor is in minor details - the use of "Hydro-form"
parts
Advantages-
 Stronger and lighter than conventional monocoque without increasing
production cost.

11. Disadvantages-
 Still not strong or light enough for the best sports cars.
Who use it ?
 Opel Astra, BMW 3-series.
 BACKBONE FRAME CHASSIS

12.  It's strong enough for smaller sports cars but not up to the job
for high-end ones.
 A strong tubular backbone (usually in rectangular section)
connects the front and rear axle and provides nearly all the
mechanical strength.
Advantages-
 Strong enough for smaller sports cars.
 Easy to be made by hand thus cheap for low-volume
production.
 Simple structure benefit cost.
Disadvantages-
 Not strong enough for high-end sports cars.

13.  The backbone does not provide protection against side impact
or off-set crash.
 Therefore it needed other compensation means in the body.
 Cost ineffective for mass production.
Who use it ?
 Lotus Esprit, Élan Mk II, TVR, Marcos.
 ALUMINIUM SPACE FRAME

14.  Consists of extruded aluminium sections, vacuum die cast
Components and aluminium sheets of different thicknesses.
 It's quite complex and production cost is far higher than steel
monocoque.
Advantages-
 Lighter than steel monocoque.
 As space efficient as it.
Disadvantages-
 Still expensive for mass production.
Who use it ?
 Audi

15.  CARBON-FIBBER MONOCOQUE
 Most so-called "supercars" use carbon-fibber in body panels
only.
 Kelvar is the most common Carbon-fibre used in motor
industry due to its highest rigidity-to-weight ratio.
Advantages-
 The lightest and stiffest chassis.

16. Disadvantages-
 By far the most expensive.
Who use it ?
 McLaren F1, Bugatti EB110SS, Ferrari F50.
Chassis Design Considerations
 Stiffness
 Weight
 Fitment and Packaging
Chassis Material Considerations
 Steel
 Aluminium

17.  AISI 1018
The chassis can be broken up into three plane structures and two
tubular sections that connect them. Starting from the front of
the chassis and working back, these sections are-
 Front Bulkhead
o It is “a planar structure that defines the forward plane of
the Major Structure of the Frame”.

18.  Front Roll Hoop
o It is “a roll bar located above the driver’s legs, in proximity to
the steering wheel.”

19.  Front Bulkhead Support System and Front Hoop Supports
Front hoop support
This is the structure which connects the front hoop and front
bulkhead.

20. Front bulkhead support system
 The bulkhead support system was made by incorporating
the front suspension box in a support structure that
supports the front hoop support, bulkhead and
triangulated with the base rod

21.  Main Hoop, Main Hoop Bracing

22.  Side Impact Structure
 Rear Suspension and Engine Housing

23. STRUCTURAL ANALYSIS
Vehicle loading
 Longitudinal Torsion
 Vertical Bending
 Lateral Bending
 Horizontal Lozenging

24. FINITE ELEMENT ANALYSIS
After finalizing the frame along with its material and cross
section, it is very essential to test the rigidity and strength
of the frame under severe conditions. The frame should
be able to withstand the impact, torsion, roll over
conditions and provide utmost safety to the driver without
undergoing much deformation. Following tests were
performed on the roll cage-
 Front impact,
 Side impact,
 Rear impact,
 Roll Over

25.  Front impact analysis
Impact load calculation:
 Using the projected vehicle/driver mass of 325 kg, the
impact force was calculated base on a G-load of 10 for
extremely worst condition.
 F = ma …. (1) = 325*10*10 = 32500 N
 Impact Time= weight*(velocity/load)… (2)
= 325*(16.67/36000) = 0.15 seconds.

26.  Rear impact analysis
Impact load calculation:
 Using the projected vehicle/driver mass of 325 kg, the
impact force was calculated base on a G-load of 10 for
extremely worst condition.
 F = ma …. (1) = 325*10*10 = 32500 N
 Impact Time= weight*(velocity/load)… (2)
= 325*(16.67/36000) = 0.15 seconds

27.  Side impact Analysis
Impact load calculation:
 Using the projected vehicle/driver mass of 325 kg, the
impact force was calculated base on a G-load of 5 for
extremely worst condition.
 F = ma …. (1) = 325*5*10
=16250N

28.  Roll Over Analysis
Impact load calculation:
 Using the projected vehicle/driver mass of 325 kg, the
impact force was calculated base on a G-load of 2 for
extremely worst condition.
 F = ma …. (1) = 325*2*10
=6500N

29. APPLIED
FORCE
MAXIMUM
STRESS
(Von-Misses)
MAXIMUM
STRESS
(Principal
Stress)
MAXIMUM
DEFORMATION
FACTOR
OF
SAFETY
FRONT
IMPACT
36000N 180MPa 149MPa 5.75mm 2.06
REAR
IMPACT
36000N 195MPa 128MPa 5.5mm 1.9
SIDE
IMPACT
18000N 161MPa 156MPa 1.65mm 2.3
ROLL
OVER
7400N 114MPa 68.17MPa 0.8mm 3.25
RESULTS