1. Suspension system in
automobiles
A project on dynamics

2. Presented by
• Shaishav siddharth berry b130518me
• Suraj kumar b130494me
• Upendra kumar b130979me

3. agenda
• Introduction
• Working principle
• Model talk

4. introduction
What is suspension
system
• Supports the vehicle
and
• cushions the ride &
Holds tire and wheel in
correct position
The purpose of the
suspension
• 1. A smooth ride
2. Accurate steering
3. Responsive
handling
4. Support the
weight of a vehicle

5. What's inside
•
• Suspension is the term given to the
system of springs, shock absorbers
and linkages that connects a vehicle
to its wheels

6. Different suspension
systems
• Conventional suspension system
• Independent suspension system
• Air suspension system
• Hydro elastic suspension system

7. Working principle -
dynamics• A suspension spring serves two purposes.
First, it acts as a buffer between the
suspension and frame to absorb vertical wheel
and suspension movement without passing it
on to the frame. Second, each spring transfers
part of the vehicle weight to the suspension
component it rests on, which transfers it to
the wheels.

8. What’s important
• Coil springs are made of special round spring
steel wrapped in a helix shape. The strength
and handling characteristics of a coil spring
depend on the following.
1. Coil diameter
2. Number of coils
3. Height of spring
4. Diameter of the steel coil that forms the
spring

9. Springs

10. facts
• The larger the diameter of the steel, the
“stiffer” the spring.
The shorter the height of the spring,
the stiffer the spring.
The fewer the coils, the stiffer the
spring.

11. Spring Rate
•
Spring rate, also called deflection
rate, is a value that reflects how
much weight it takes to compress a
spring a certain amount.

12. SHOCK ABSORBERS
•
Shock absorbers are used on all
conventional suspension systems to
dampen and control the motion of the
vehicle's springs. Without shock
absorbers (dampers), the vehicle would
continue to bounce after hitting bumps

13. Why shock absorber

14. What’s the dynamics
• Spring rate is a ratio used to measure how resistant a
spring is to being compressed or expanded during
the spring's deflection. The magnitude of the spring
force increases as deflection increases according to
Hooke's Law.
• F = -kx
• where
• F is the force the spring exerts
• k is the spring rate of the spring.
• x is the deflection of the spring from its
equilibrium position (i.e., when no force is applied
on the spring)

15. dynamics
• When a wheel strikes a bump, there is a reaction
force, and energy is transferred to the spring which
makes it oscillate. Oscillations left uncontrolled can
cause loss of traction between the wheel and the
road surface.
• Shock absorbers dampen spring oscillations by
forcing oil through small holes. The oil heats up, as
it absorbs the energy of the motion. This heat is
then transferred through the body of the shock
absorber to the air.

16. dynamics
• When a vehicle hits an obstruction, the size of the
reaction force depends on how much unsprung
mass is at each wheel assembly
• Unsprung mass includes the wheels, tires, brake
assemblies, and suspension parts not supported by
the springs.
• Sprung mass refers to those parts of the vehicle
supported on the springs. This includes the body,
the frame, the engine, and associated parts

17. Spring rate
• The spring rate (or suspension rate) is a component in
setting the vehicle's ride height or its location in the
suspension stroke. When a spring is compressed or
stretched, the force it exerts is proportional to its change in
length. The spring rate or spring constant of a spring is the
change in the force it exerts, divided by the change in
deflection of the spring. Vehicles which carry heavy loads
will often have heavier springs to compensate for the
additional weight that would otherwise collapse a vehicle
to the bottom of its travel (stroke).

18. Spring rate
• The spring rate of a coil spring
K=Gd4/8ND3
• where d is the wire diameter, G is the spring's shear modulus
(e.g., about 12,000,000 lbf/in² or 80 GPa for steel), and N is
the number of wraps and D is the diameter of the coil.
Spring rates typically have units of N/mm (or lbf/in). An
example of a linear spring rate is 500 lbf/in. For every inch
the spring is compressed, it exerts 500 lbf.

19. Model talk
• Made of wood
Shows you
• wheels
• Axle
• Shaft
• Springs

20. Model view

21. Model in hostel

22. Thank you