• Whiplash injury is the most common injury associated with low-speed rear end collisions• The cost of whiplash injury in British Columbia:

• 70% of all insurance injury claims• 2006: ~ $850 million dollars1

• Across Canada, the cost of whiplash is over $8 billion dollars• The incidence of whiplash injury globally ranges from:

• 28 to 834 cases per 100,000 population annually2,3

• > 1% of the population• 14 to 42% of whiplash-associated disorder (WAD) cases develop chronic neck pain, and nearly 10% will be left with permanent severe pain and disability4

Project A505-ARI - Prevention: Injury Prevention Through Adaptive Seat Design

THE UNIVERSITY OF BRITISH COLUMBIA

Mechanical Engineering & School of Kinesiology

Support provided by:

Why is Studying Whiplash Important?

Actively Controlled Seat Development

Current Anti-Whiplash Devices

During Impact – Actively Control Seat Hinge Rotation

A Legacy of Collaboration

Pre-Impact – Occupant Mass Sensor

References

http://chubzo.hubpages.com/hub/what-is-scar-tissue

http://cdn1.automobilesreview.com/2008/12/volvo-v70-whips.jpg

http://www.saabhistory.com/blog/wp-content/uploads/2006/12/1097144.jpg

Fig. 7 – Viano (2008) Traffic Inj. Prev. (9)6

• Over 12 billion dollars is spent annually on the research and development of car seats and safety devices; however, only 51% of manufactured car seat models received the highest rating for protecting against severe whiplash injury6

• This motivates our development of an actively controlled car seat, which will reduce the risk of whiplash injuries in Canada and around the world

• The successful development of our actively controlled adaptive car seat is due to the collaboration between supervisors, graduate students, and undergraduate students from both Engineering and Kinesiology.

• In the future we plan to test human occupants to further develop the adaptability of our car seat for occupants of different anthropometry

• When implemented into vehicles, our actively controlled car seat will adapt to an occupant’s anthropometry and generate a seatback rotation profile that will best protect that occupant during a rear-end collision to reduce the risk of whiplash injuries for all Canadians

[1] ICBC (2007) Annual Report, British Columbia [2] Cassidy et al. (2000) N Engl J Med 342(16): 1179-86. [3] Holm et al. (2008) Spine 33(4 Suppl): S52-9. [4] Barnsley et al. (1994) Pain 58(3): 283-307.[5] Romilly & Skipper (2005) SAE Trans. 114(6): 1512-20.[6] Thatcham Research News (2010) thatcham.org. Sp. Ed. No. 1.

• As part of the pre-impact measurements, we designed and prototyped a custom force plate sensor mounted to the seat base to determine an occupant’s mass when seated in a car seat (Fig. A. & Fig. B.)

• Four load cells were used to increase the sensitivity of the system to changes in occupant mass• The occupants would be categorized into different weight groups to select optimal seat hinge and seatback cushion

properties to be implemented by the actively controlled car seat during rear-end collisions (Fig. D.)

Project Objective

• Current approaches modify seat mechanics to reduce the risk of whiplash injuries by reducing occupant accelerations and minimizing the movement of the head relative to the upper torso

• Volvo WHIPS seat (top)• GM High Retention Seat (right top) • Saab Active Head Restraint (SAHR) (bottom)

• Although beneficial, these designs are passive and cannot adapt to occupant mass or impact severity

• To design and prototype an actively controlled car seat to reduce the forces and accelerations applied to occupants during low-speed rear end collisions

• Key design features:1. Pre-impact: Accounts for

occupant mass to adjust seat hinge and seatback cushion properties

2. During impact: Actively controls seat hinge and cushion properties based on impact severity

LS-Dyna Simulation

Preliminary CAD Prototpye

Project Outline Design Tools

8 km/h Control 12 km/h Control 16 km/h Control 8 km/h Optomized 12 km/h Optomized 16 km/h Optomized

D. Prototype Test

• Computational Test: To validate the concept of our actively controlled seat, a LS-Dyna simulation of a simplified car seat5 with a Hybrid III ATD was utilized (Fig. A.)

• When compared to the standard control seat, the optimized solutions reduced resultant T1 acceleration by 59%, 57%, & 58% for the 16km/h, 12km/h, & 8km/h impacts respectively (Fig. B.)

• These reductions were achieved by delaying the timing and increasing the magnitude of the peak rotational velocity of the seatback, also reducing the rebound velocity to zero (Fig. C.)

• Prototype Test: The actively controlled car seat was then prototyped and tested with a BioRID II ATD (Fig. D.)• Experimental seatback rotations are defined by three parameters to reduce occupant rebound velocity during a collision:

i.) peak initial rotational velocity, ii.) peak amplitude, and iii.) onset of seatback rotation.• Exemplar seatback rotation (Fig. F.; i.) 9.9 deg/s peak initial rotation, ii.) 100% peak amplitude, and iii.) +20 ms onset delay)

reduced resultant T1 acceleration by 29% when compared to the standard control seat during a 12km/h impact (Fig. E.)• Our prototype testing were similar to our earlier computational tests and demonstrated the potential to reduce occupant

loads through an actively controlled seat• Further investigation is needed before determining optimum seatback rotations for different rear impact load cases

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