Airbags and Seatbelt

8/14/2019 Airbags and Seatbelt

1/14

BY

K.SUGANESWARAN

AIRBAGS AND SEATBELT


2/14

AIRBAGS

In the 1980s the first commercial air bags appeared inautomobiles.

Air bags are most commonly used for cushioning, in

particular after very rapid inflation in the case of an

automobile collision.

The safety belts, primarily restrain the occupants torso and

pelvic movements, however, the instantaneous head, neck

rotations cannot be prevented by the safety belts.

The air bags supplements seat belt in this function byproviding soft cushion between occupants head and

steering / dash board.


3/14

CONT

This prevents direct contact between occupantshead and rigid vehicle interiors and evenly

distributing the forces on occupants face.


4/14

TYPES

Frontal air bags

Door mounted side head airbags

Knee air bags

Side curtain air bags

Air bag for pedestrian protection on front hood of

vehicle(under research)


5/14

WORKING

The bag itself is made of a thin, nylon fabric Polyamide(PA) or Polyester (PETP) partially with blow-out holes for

controlled cushion, which is folded into the steering wheel.

The sensor is the device that tells the bag to inflate.

The sensors receive information from an accelerometerbuilt into a microchip.

The air bag's inflation system reacts with Sodium Azide

(NaN3) with Potassium Nitrate (KNO3) to produce nitrogen

gas.

Hot blasts of the nitrogen inflate the air bag.


6/14

CONT


7/14

CONT

The air bag system ignites a solid propellant, which burnsextremely rapidly to create a large volume of gas to inflate

the bag.

The bag then literally bursts from its storage site with the

speed up to 322 km/h - faster than the blink of an eye. A second later, the gas quickly dissipates through tiny holes

in the bag, thus deflating the bag .

Cornstarch or talcum powder is used for effective

lubrication.


8/14

TECHNICAL COMPLEXITIES

The decision whether to deploy or not to deploy are doneby airbag triggering algorithm.

Inputs coming from the crash sensors which in turn dependon crashworthiness of individual vehicle structures.

Many times real life accidents do not generate crash forcesenough to trigger the airbag to deploy.

If occupant is sitting close to the airbag less than teninches, the risk of occupant getting seriously injured by thedeployment of airbag itself increases many fold.

Children can get seriously injured even fatal injuries cantake place if unbelted child is sitting very close to theairbag.


9/14

SEATBELT ANCHORAGES

Restraint systems integrated with occupants seat haveshown improved occupant safety and decreased risk of

injuries during motor vehicle impacts .

A seat belt or safety belt is a safety harness designed to

secure the occupant of a vehicle against harmful movementthat may result from a collision or a sudden stop.

Seat Belts are intended to reduce injuries by stopping the

wearer from hitting hard interior elements of the vehicle.

Seat belts also absorb energy by being designed to stretchduring any sudden deceleration.


10/14

CONT

Spreads the loading of impact on the passengersbody.

An arrangement of straps with a securing buckle, adjusting

devices and attachments which are capable of being

anchored to the interior of a motor vehicle .

Designed to diminish the risk of injury to the wearer in theevent of collision or of abrupt deceleration of the vehicle,

by limiting the mobility of the body of the wearer.


11/14

TYPES

Two Point (Lap) Belt

Three Point Belt

Harness Belt


12/14

CONT

A seat belt retractor is a device having a gas generator forgenerating a high pressure gas when a vehicle is in

emergency.

Chamber cylinder for conducting the high pressure gas

from the gas generator, a piston received movably withinthe chamber cylinder and pressed and moved by the high

pressure gas.

Piston having an O ring sealed end portion engaging walls

of the chamber cylinder and a rack portion extending intothe chamber cylinder and finally tighten the belts.


13/14

Cont


14/14

Documents

Airbags and Seatbelt