The Helmet Doctors

An Inside Look

A Closer Look at How the Insides Are Impacted on Impact

 

Ensuring our scientific understanding of helmet inspections, we investigated, dissected, and drop-tested various helmets with the assistance of the University of Queensland and Crashlab- the Centre for Road Safety, Transport Department of New South Wales.

 

 

Cashlab testing facilities are world-class, to Australian Standards and Australian Design Rules.

Crashlab maintains compressive National Association of Testing Authorities (NATA), Australian and international accreditation for compliance and helmet testing.

 

 

Physical inspections, scientific measurements & many before & after (drop test) images were taken, using the Non-Destructive Laser technique of Holographic Interferometry providing an inside look and evidence of our Laser Scanning technique.

 

 

What is the Problem?

Upon impact, a motorcycle helmet’s first line of defence is for the shell to flex and dissipate 34% of the impact energy , then ultimately absorb the rest through the EPS foam. Nowadays, helmets do this so well that they don’t appear to be impacted at all.

Internal Damage to the EPS foam

In the above example, the danger lies when the helmet has taken an impact but there is no evidence on the outside of the shell or inside of the EPS foam. Therefore, the helmet has done its intended job and you have avoided a possible TBI or even premature death.

 

Below is a short video showing what “An Inside Look” at damaged EPS foam.

In this case, we only concern ourselves with the likes of a Flat Anvil Impact and a Hemispherical (Hemi) Anvil Impact. This is because the spike test would result in a piercing of the outer shell, which would render the helmet damaged because it would be visible to the naked eye.

 

As we know the outer shell of the helmet is more effective at dissipating shock than the EPS interior. The integrity of the EPS liner becomes immaterial if the outer shell has been compromised, ie the helmet then becomes no longer fit for use.

 

Generally speaking, there’s a possibility the integrity of the EPS liner could become compromised from the inside, but with normal use the liner should generally outlast the outer shell.

 

Upon visual inspection of the inside EPS liner, the degradation of the EPS liner will be apparent if it is present. Most helmet manufacturers coat the white EPS with a material that resembles black paint. When inspecting the inner liner, if you see white speckling, cracking, or splitting of the EPS foam, this implies the liner has deteriorated or suffered an impact that will automatically render the helmet damaged.

 

Internal Damage to Composite Materials

Here’s a schematic diagram and a microscopic view of how composite materials react to impact. Observe that the vast majority of damage does not occur at the point of contact but rather at the back of the material.

With our Laser Scanning Cameras, The Helmet Doctors can identify, read, record, and measure these defects on your helmet.

 

An Inside Look – after drop test

During our Helmet Drop Testing at Crashlab, we put through an extensive number of helmets and drop tested them with a combination of various heights. Our challenge was to confirm our laser scanning camera could identify defects within the helmet’s structural integrity before the helmet owner could realize, they were in danger of using a defective helmet.

 

According to the Hurt Report, a drop of about 2 meters, or 6.6 feet represents the 90th percentile of crashes & a 10-foot drop (3 meters) represents the 99th percentile of impacts.

For our testing, the energy of each drop, we selected a range of hits typical of both the ECE22.05 and AS/NZS1698 testing regimens. We hit the front right and the rear left of the helmets with an average energy of 190g, using an AS/NZS1698 (drop height of 1830mm x2) and an average energy of 219g, using an ECE22.05 (drop height of 2860mm x1).

 

We also did a low-energy drop with an average energy of 114g, using an AS/NZS1698 (drop height of 1385mm x2) onto a Hemispherical Anvil.

In summary, the range of heights and g’s put our testing into the AIS4 and AIS3 categories and an average HIC range of 530 to 2034.

 

Our extensive testing concluded, upon impact, helmets react in various way due to the various manufacturing techniques & materials used, the age & condition of the helmet, and also the height and type of impact endured.

 

Our takeaway was that our laser scanning camera can see as low as 10nm with a resolution & clarity like no other, The Helmet Doctors can identify these defects inside the helmet at much lower levels of impact.

Looking at the average levels of impact shows, it shows there is a 20% chance the person in the helmet may have resulted in a concussion. On the flip side, this means there is an 80% chance the helmet owner may not have even realized the helmet was even impacted or the helmet has now been compromised.

 

Our view is, and always will be, if you know you have hit your helmet during an impact just replace the helmet with a brand-new helmet. It’s only when you are unsure if you did or did not hit your head that our services will be of great benefit, giving you peace of mind and protection.

 

An Inside Look - Flat Anvil Impact

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Test Results

Maximum: 156.0 g at 14.9 ms

HIC 15: 1076.9, T1: 11.8 ms T2: 17.4 ms (t2-t1): 5.7 ms

Test Information

Test Details

Test Type: Energy Attenuation

Project: P.0020129.11

Test Number: H1901020

Drop: 1

Specimen: TS65266

Manufacturer: KBC

Model: Kombat

Size: M

Headform:  J

PI: 50 mm

Condition: Ambient

Test Site: A

Anvil: Flat

Drop Height: 1830 mm

Colour: P.C.

Client: The Helmet Doctor

Test Information

Test Details

Test Type: Energy Attenuation

Test Number: H1901021

Drop: 1

Specimen: TS65266

Manufacturer: KBC

Model: Kombat

Size: M

Headform:  J

PI: 50 mm

Condition: Ambient

Condition: Ambient

Anvil: Flat

Drop Height: 1830 mm

Colour: P.C.

Client: The Helmet Doctor

Test Results

Maximum: 179.5 g at 15.3 ms

HIC 15: 1293.7, T1: 12.6 ms T2: 17.8 ms (t2-t1): 5.2 ms

An Inside Look - Hemispherical Anvil Impact

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Test Results

Maximum: 109.4 g at 16.1 ms

HIC 15: 468.2, T1: 14.4 ms T2: 23.0 ms (t2-t1): 8.5 ms

Test Information

Test Details

Test Type: Energy Attenuation

Project: P.0020129.11

Test Number: H1901029

Drop: 1

Specimen: TS65266

Manufacturer: KBC

Model: Kombat

Size: M

Headform:  J

PI: 50 mm

Condition: Ambient

Test Site: B

Anvil: Hemi

Drop Height: 1385 mm

Colour: P.C.

Client: The Helmet Doctor

Test Information

Test Details

Test Type: Energy Attenuation

Project: P.0020129.11

Test Number: H1901030

Drop: 1

Specimen: TS65266

Manufacturer: KBC

Model: Kombat

Size: M

Headform:  J

PI: 50 mm

Condition: Ambient

Test Site: B

Anvil: Hemi

Drop Height: 1385 mm

Colour: P.C.

Client: The Helmet Doctor

Test Results

Maximum: 107.6 g at 16.4 ms

HIC 15: 543.7, T1: 15.1 ms T2: 22.5 ms (t2-t1): 7.4 ms