Airbag: Life saving textiles

The airbag fabric may be coated to increase the strength of the fabric so that the fabric is reinforced, and by increasing the strength of the fabric, breakage of the airbag can be minimised, assert R Senthil Kumar and S Sundaresan.

Technical textiles are gaining fast recognition as one of the most dynamic and promising areas for the future of the textile industry in India for high-performance applications. Automotive textiles happen to be a rewarding sector finding extensive use of technical textiles in the product categories, viz, interior trims, safety devices like seat belts and airbags, carpets, filters, battery separators, hood liners, hoses and belt reinforcement. Airbags are a type of automobile safety restraint like seat belts. The aim of this article is to give broad outlook about the importance of airbag, working of airbag, types of airbags, fibres and fabrics used and manufacturing of airbags.

Airbags are gas-inflated cushions built into the steering wheel, dashboard, door, roof, or seat of your car that use a crash sensor to trigger a rapid expansion to protect you from the impact of an accident. The working of airbag is precision application. In just 0.03 seconds airbags should begin and by 0.06 seconds after crash bag should be fully inflated. Airbag may build into steering or in some other strategic location. Mostly, nitrogen gas is used in airbags.

In most countries airbags are mandatory for all passenger cars due to stringent in legislation. In 2002 alone, airbags system has contributed up to 20 per cent reduction in fertilities resulting from front collision. Earlier airbags were considered as substitute to seat belts and were only limited up to high speed sports cars. But today, airbags are working in co-ordination with seat belts. In fact, airbags cushion an occupant in an event of crash. This helps in avoiding the heat on collision. Size of airbags may vary according to position. The concept of the airbag — a soft pillow to land against in a crash — has been around for many years.

Airbag working

Airbags inflate, or deploy, quickly — faster than the blink of an eye. Imagine taking one second and splitting it into one thousand parts. In the first 15 to 20 milliseconds, airbag sensors detect the crash and then send an electrical signal to fire the airbags. Typically a squib, which is a small explosive device, ignites a propellant, usually sodium azide. The azide burns with tremendous speed, generating nitrogen, which inflates the airbags. Within 45 to 55 milliseconds the airbag is supposed to be fully inflated. Within 75 to 80 milliseconds, the airbag is deflated and the event is over.

When airbags work properly, they dramatically reduce the chance of death or serious injury. However, the speed with which airbags inflate generates tremendous forces. Passengers in the way of an improperly designed airbag can be killed or significantly injured. Unnecessary injuries also occur when airbags inflate in relatively minor crashes when theyre not needed.

Laws of motion

The moving objects have momentum (the product of the mass and the velocity of an object). Unless an outside force acts on an object, the object will continue to move at its present speed and direction. Cars consist of several objects, including the vehicle itself, loose objects in the car and, of course, passengers. If these objects are not restrained, they will continue moving at whatever speed the car is travelling at, even if the car is stopped by a collision.

Stopping an objects momentum requires force acting over a period of time. When a car crashes, the force required to stop an object is very great because the cars momentum has changed instantly while the passengers has not there is not much time to work with.