Parametric analysis of an anti-whiplash system composed of a seat suspension arrangement

  • Mustafa Özdemir
  • Sıtkı Kemal İder
  • Mustafa İlhan Gökler
Technical Paper


Neck injuries frequently seen in low-speed rear-end collisions are referred to as whiplash injuries. Most of the proposed anti-whiplash systems in the literature rely on reducing the backset. A relatively new and promising alternative concept is a slideable seat. This study aimed to parametrically analyze an anti-whiplash vehicle seat that can slide backward against a horizontal suspension arrangement composed of a spring and a damper in response to a rear-end collision, and to investigate the effects of the suspension parameters on the injury risk. A simplified model of a slideable vehicle seat is developed, and simulations are conducted in LS-DYNA® environment using this slideable seat model and the commercially available finite element model of the BioRID II dummy. The maximum value of the Neck Injury Criterion (NICmax) is used as the measure of the injury risk. As a result, a strong linear inverse correlation is observed between NICmax and the maximum seat sliding distance, while the stiffness and damping coefficients of the suspension are varied. This result is also verified by obtaining the same NICmax value for the same maximum seat sliding distance (although the stiffness and damping coefficients are different). It is also shown that, for a given backset value as large as 60 mm, a slideable seat with the suspension parameters selected to yield a reasonable maximum seat sliding distance such as 100 mm significantly improves NICmax compared to a standard seat. As the maximum seat sliding distance is increased, the injury risk becomes smaller.


Whiplash Safety Rear impact Neck injury 

List of symbols

\(a_{\text{head}} (t)\)

Horizontal acceleration of the center of gravity of the head

\(a_{T1} (t)\)

Horizontal acceleration of the first thoracic vertebrae


Backset distance


Damping coefficient of the anti-whiplash seat suspension damper


Maximum sliding distance of the seat


Initial bias force of the anti-whiplash seat suspension spring


Stiffness of the anti-whiplash seat suspension spring


Neck Injury Criterion




Amount of the initial compression given to the anti-whiplash seat suspension spring



The authors would like to thank Hüseyin Dicle, Evren Anık, and Murat Sefa İnce, at the Seat Design Management of TOFAŞ R&D Directorate, for their valuable discussions. Additionally, Mustafa Özdemir is thankful to the Scientific and Technological Research Council of Turkey (TÜBİTAK) for the support provided through the National Scholarship Programme for PhD students. Last but not least, thanks to the METU-BILTIR Center Vehicle Safety Unit for the facilities provided.


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Copyright information

© The Brazilian Society of Mechanical Sciences and Engineering 2014

Authors and Affiliations

  • Mustafa Özdemir
    • 1
    • 2
  • Sıtkı Kemal İder
    • 3
  • Mustafa İlhan Gökler
    • 1
    • 2
  1. 1.Department of Mechanical EngineeringMiddle East Technical UniversityÇankayaTurkey
  2. 2.METU-BILTIR CenterMiddle East Technical UniversityÇankayaTurkey
  3. 3.Mechanical Engineering DepartmentÇankaya UniversityYenimahalleTurkey

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