Helmets are designed to absorb impact forces and protect the rider’s head in the event of an accident.

Despite the exhilarating feeling of wind in our hair, motor authorities are always concerned about it…and for good reason!

The brain is the most vital organ in our body, and riding a bike exposes it to potential harm.

Helmets are essential in all motorsports (Photo Credit: Pixabay)

Unlike other physical injuries, brain damage can have long-term or irreversible consequences. Therefore, wearing protective gear while biking cannot be stressed enough.

What’s Inside a Helmet?

When we think of motorcycle safety, helmets are the first thing that comes to mind. While they do not prevent accidents, they greatly reduce potential damage during a crash.

A helmet consists of various parts, each designed for comfort, aesthetics, and most importantly, safety.

1. Outer Shell

The outer shell is the visible and outermost part of the helmet. It serves as its protective layer. Common materials used for shells include polycarbonates, ABS, fiberglass-reinforced plastics, and composites like carbon fiber and Kevlar.

The outer shell is designed to crack slowly and provide abrasion resistance during sliding.

2. Impact-Absorbing Liner

The impact-absorbing liner is the core of the helmet. It is made of expanded polystyrene (EPS), which can withstand high shock and compression loads.

3. Foam Liner

The foam liner is a cushioning surface between the EPS liner and the rider’s head. It consists of foam pads that securely hold the head in place and absorb moisture from sweat. A good foam liner prevents any movement between the head and the helmet.

4. Retention System

The retention system includes straps that fasten under the neck to keep the helmet in place. They ensure the helmet remains secure on the head during impact.

5. Face Shield

Face shields, also known as visors, cover the view port of the helmet while allowing the rider to see clearly. They are typically made of hard, shatter-proof polycarbonate to protect the rider’s eyes from airborne debris.

6. Ventilation System

The ventilation system, although not directly related to primary safety, is an integral part of it. It allows air circulation within the helmet, keeping the rider comfortable and preventing fogging of the visor due to breath moisture.

How Helmets Function

In terms of physics, an accident involves a large mass coming to a sudden stop within a fraction of a second and a few millimeters of distance. The body experiences deceleration of several hundred Gs, with 1G being the gravitational pull of the earth.

Helmets absorb the majority of the impact and transfer very little to the rider’s head (Photo Credit : Shutterstock). The human body is not capable of handling such intense shocks, some of which can be fatal. A well-designed helmet has two lines of defense: the outer shell and the EPS liner.

During an impact, the outer shell absorbs the initial hit and develops cracks that spread slowly, reducing the amount of energy transferred to the EPS liner. Since the EPS is compressible, most of the remaining force is absorbed by compressing it, resulting in minimal energy being transferred to the rider’s head.

According to industry standards, a helmet is considered roadworthy if it offers force penetration of less than 300G to the rider’s head.

Testing And Certification Of Helmets

Unlike car crashes, it is not possible to simulate motorcycle accidents due to the numerous unknown variables involved. However, manufacturers must adhere to standards that certify helmets as safe for road use. These standards become more stringent over time, ensuring the production of progressively safer helmets.

Helmets are typically tested for both linear and rotational head movements. A head-form is placed inside the helmet to simulate the rider’s head. Sensors are used to measure the impact at various points.

Before being made available to customers, a typical roadworthy helmet undergoes the following tests:

1. Impact Management

The impact resistance of a helmet is tested through destructive tests such as collision tests, drop tests, and penetration tests. These tests involve dropping the helmet at different velocities onto anvils with different profiles. Impact resistance assesses the integrity of the shell by measuring its ability to develop slow propagating cracks and reduce forces transmitted to the head-form.

Another important test is the abrasion test, which evaluates the helmet’s ability to slide against tarmac. A helmet that slides easily prevents twisting forces on the neck, thereby reducing the risk of spine injuries.

2. Positional Stability

This non-destructive test determines the helmet’s tendency to roll off the rider’s head during an impact. The helmet is suspended upside down at approximately 45 degrees and loaded at its edges. The suspension mechanism’s elongation is measured during a guided free fall. If the elongation exceeds 5mm, the helmet is considered unsafe as it would roll off the rider’s head.

3. Retention Strength

In this test, the retention mechanism of the helmet is subjected to tensile loads until failure. A roadworthy helmet’s retention mechanism should be able to withstand shock loads of up to 400 kg. If the retention mechanism fails before the straps, the helmet will come off during a crash and is therefore unsafe for road use.

4. Area Of Coverage

A helmet’s design involves a trade-off between maximum coverage and maximum visibility. Helmets are tested for good primary and peripheral fields of vision. A helmet with a narrow view port and limited peripheral vision, while providing better crash safety, cannot be used on the road. On the other hand, a larger view port weakens the helmet’s shell, making it hazardous.

Commonly accepted helmet standards include US DOT, Europe’s ECE 22.05, Snell, and SHARP.

The Advancements in Helmet Safety and Communication

As composites and simulation techniques continue to advance, helmets are becoming even safer for riders. Additionally, modern helmets now have wireless communication capabilities, making them more useful than ever. However, it is crucial to emphasize the importance of wearing a helmet, whether you are riding a motorcycle, a bicycle, or any other mode of transportation.