- A concussion occurs at roughly 90 to 100 g-force
- However, helmets are not designed to prevent concussions, because though it can externally soften the blow, your brain still might hit the inside of your skull due to rotation and linear forces.
- Helmets are effective in preventing skull fractures and very serious brain injuries
- Studies have shown that 26–49 % of surfing injuries involve the head and occasionally result in loss of consciousness and drowning, so it makes sense for surfers to wear helmets. Although surfing-specific helmets are commercially available, studies have shown that few use them. Many surfers perceive helmets as restrictive, feel they restrict hearing and sense of balance, and are concerned that the additional surface area will interfere with duck diving
Can air stop head injuries?
- Hövding inflatable bike helmets are 12 cm thick and inflated to 50 kPa
- Airbag helmets achieve up to an 8-fold reduction in the risk of concussion compared to standard EPS helmets.
- Furthermore, we construct an optimization framework for airbag helmets to minimize concussion and severe head injury risks at different impact velocities, while avoiding excessive deformation and bottoming-out.
- An optimized airbag helmet with 0.12 m thickness at 72 ± 8 kPa reduces the head injury criterion (HIC) value to 190 ± 25 at 6.2 m/s head impact velocity compared to a HIC of 1300 with a standard EPS helmet. Based on a correlation with previously reported HIC values in the literature, this airbag helmet design substantially reduces the risks of severe head injury up to 9 m/s.
- HIC of 1000 corresponds to 50% risk of skull fracture,22 a HIC of 700 is estimated to represent a 5% risk of a severe injury,31 and a HIC of 250 to represent a 50% risk of concussion in athletes
- There is a crucial trade-off between helmet thickness and performance in helmet design.
- Increasing the thickness of a helmet for a soft helmet has a pay-off in its performance, until 12 cm, after which it has marginal improvements
- The pressure of the optimum airbag helmet decreases as the thickness increases since the equivalent elastic stiffness needs to be smaller.
- We choose our optimum helmet design to be an airbag helmet with a thickness of 12 cm, pressure value of 72 ± 8 kPa, which reduces the HIC value to 190 ± 25 at 6.2 m/s head impact
- We can do our own set of calculations using whatever thickness we determine to create our own version of this graph, which will allow us to find the optimal pressure. 50% concussion (HIC = 250), 5% severe head injury (HIC = 700) and 50% skull fracture (HIC = 1000)
- Limitations of this study:
- Only considered linear accelerations, but rotational accelerations can also cause concussions
- Did not consider how would impact neck injuries
- Tested Hövding airbag helmet, which performed 3x better than conventional helmets in a linear acceleration test
- 48 g vs the average 175 g
- The Hövding 2.0 also obtained very good results in the rotational tests, and was the only helmet that did not give results that exceeded the threshold for 50% risk of concussion.
- This shows that inflatable helmets are better than traditional helmets for linear AND rotational impacts. (Assuming it deploys in time).