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					                           Thatcham
International Dynamic Testing for
            Whiplash
     Matthew Avery Thatcham

            May 2005
Thatcham
Safety Improvements
The role of the consumer test
Soft Tissue Neck Injuries - Whiplash
UK Insurer Perspective


   Whiplash – The most frequently reported injury in motor
    vehicle crashes
   10% of injuries – long term (+1 month)
   1% of injuries permanent
   Predominantly occurs in rear crashes
   250 000 cases annually in UK
   Current homologation requirements do not address issue
UK WAD Problem?
UK Motor Insurance Costs
UK Insurer Costs


     70% Material Damage           6% Security




                                 24% Personal Injury



                   €10 Billion
UK Motor Insurance Costs
UK Insurer Costs



                              80+% WHIPLASH

 24% Personal Injury




          Costing the UK Insurance Industry
             approx €2 Billion Annually
Soft Tissue Neck Injuries - Whiplash
Fundamentals – What DO and DON’T know

  Whiplash – Caused by the rapid differential movement of
    the OC relative to T1
  Injury mechanisms – subject of many years of international
    research but still poorly understood
  Injury criteria proposed:
    NIC (Neck Injury Criteria)
    NKm
    Rebound Velocity
 Relate to unproven “theoretical” injury mechanisms
Head Restraints
Real World Usage
Head Restraints
Real World Usage
Head restraint measuring device
Thatcham Geometric rating for head restraints
International standard through RCAR
                                           4


                                           2
               Distance above/below top
                of average male’s head
                                           0


                                           -2


                                           -4
                                                good
                                           -6
                                                acceptable
                                           -8
                                                marginal
                                          -10

                                                poor
                                          -12


                                          -14


                                          -16


                                          -18
                                                2      4   6   8    10    12   14   16   18

                                                               backset (cm)
Most head restraints have Acceptable & Good Geometry
Thatcham evaluations in model years 2001 and 2004




           2001                             2004

          Good     Acceptable    Marginal      Poor
 Improved head restraint geometry reduced injury claims
 Farmer, Wells & Lund (IIHS, 2002)




 1999                                          Neck Injury
 Ford                                         rear crashes -
Taurus                                            24 %




                                                Neck injury
 2003                                          Rear crashes -
 Ford
                                                   20 %
Taurus
   Seats with initially acceptable/good geometry
   don’t always perform well dynamically




Seat height adjustor failure & seatback      Too soft head restraint
      deflection defeat good geometry     defeats acceptable height
International Insurance Whiplash Prevention Group
Dynamic Whiplash testing aims


   Develop dynamic tests and evaluation criteria to
    compare and rate seat and head restraint designs for
    consumer information
   Encourage manufacturers to design and develop
    effective anti-whiplash systems to reduce real world
    injuries
   Ultimately establish minimum neck protection
    requirements for regulation
International Insurance Whiplash Prevention Group
Members and Countries – A global community

   Thatcham - UK
   IIHS – USA
   GDV – Germany
   Folksam - Sweden
   IAG – Australia
   ICBC – Canada
   Cesvi - Spain
The IIWPG dynamic test
The Three principles of the IIWPG
Seat Assessment Test
  1. Require adequate geometry to protect all
    occupants
  2. Encourage the adoption of seat design attributes
    shown to reduce whiplash injury
    – Limit acceleration of the torso
    – Limit time until head is supported by head restraint
  3. Reduce the work the neck does in a rear crash
    – Limit neck tension force
    – Limit neck shear force
Dynamic test philosophy
1. Geometry

   Seats with Marginal or Poor geometric ratings are
    rated Poor by default – since they offer inadequate
    geometry
   Seats with Acceptable or Good geometry are tested to
    the 16 Km/h dynamic test
   Ratings are based on their dynamic performance but
    in some cases are modified to ensure protection of
    taller adults
Dynamic test philosophy
2. Seat Evaluation Criteria


   Control the energy transferred to the occupant during
     the crash by limiting thoracic accelerations (Volvo
     Whips)
   T1 acceleration Limit 9.5g
   Limit the time with which the head is unsupported by
     the head restraint (Saab 95)
   HRC limit (70ms)
   Seat Evaluation Criteria “PASS or FAIL”
Examples of Seats with good seat design
characteristics
Saab 93 with reactive HR and Volvo V70




    Saab 93                     WHIPS
   HR contact                  T1xg = 6.7
    = 47 ms
Real World Injury Reduction
Reduction of neck injury claims in rear crashes by seat compared
with predecessors
Dynamic test philosophy
3. Limit the work the neck does in a rear crash by
limiting neck tension and rear shear forces



                                Neck shear force


                                 Neck tension
Dynamic test philosophy
3. Neck Force Ratings

   Reduce the work the neck does in a rear crash by
    limiting neck tension and neck shear forces
   Upper neck Force and Tension limits based upon bi-
    variant joint probability distribution scheme
   Thresholds based on 30th%ile and 75th%iles of
    European and US seats tested (250)
   Zones give ratings of Low , Moderate or High neck
    forces
Neck forces will be graded on a scale of low,
moderate, and high
   Dynamic Rating based on sled test result

        Seat Design Parameter       Neck Force Rating Dynamic Rating

        T1 x-acceleration ≤ 9.5 g         LOW             GOOD
PASS




                   Or                 MODERATE         ACCEPTABLE
       Time to HR contact ≤ 70 ms        HIGH           MARGINAL

        T1 x-acceleration > 9.5 g         LOW          ACCEPTABLE
FAIL




                  And                 MODERATE          MARGINAL
       Time to HR contact > 70 ms        HIGH              POOR
Geometry Rating   Dynamic Rating    Overall Rating
                      GOOD             GOOD
                  ACCEPTABLE        ACCEPTABLE
    GOOD
                    MARGINAL         MARGINAL
                      POOR             POOR
                      GOOD          ACCEPTABLE
                  ACCEPTABLE        ACCEPTABLE
 ACCEPTABLE
                    MARGINAL         MARGINAL
                      POOR             POOR
  MARGINAL
                  No dynamic test      POOR
    POOR
2005 IIWPG Dynamic Tests
Small Cars – Poor to Good




    MARGINAL                  GOOD
   BMW 1 Series             Ford Focus II
Dynamic Test Comparison
A Good and Poor Performer
Thatcham (IIWPG) Ratings
International launch of ratings in Europe, North America and Australia
IIWPG Dynamic Test Ratings
Publication of 2005 dynamic results

   Results launched Internationally on November 15th
   125 – European by Thatcham
   97 – US by IIHS
   November 15th Global whiplash results release
   Thatcham, GDV, IAG (European)
   IIHS, ICBC, IAG (North American)
   Results fed into Euro NCAP
Thatcham Seat Ratings
125 Cars seats rated




         WWW.Thatcham.org
2005 IIWPG Dynamic Tests
Thatcham (Europe) evaluations of Dynamic Tests Results -
Percentage
                                   24%




             Good     Acceptable    Marginal    Poor
Insurance Institute for Highway Safety Seat Ratings
97 Car seats rated




     WWW.highwaysafety.org
2005 IIWPG Dynamic Tests
IIHS (USA) evaluations of Dynamic Tests Results - Percentage
                     17%




                                   55%



             Good     Acceptable    Marginal     Poor
Will Dynamic Testing Lead to better designs?
It’s already driving new designs...




   VW Golf mk 4      Poor             VW Golf mk 5 Acceptable
Even better protection
Future design concepts driven by IIWPG dynamic testing




     Active Head                   Active Head
      Restraint                     Restraint
       Keiper                          CRH
IIWPG and Thatcham; The future
2005 research and launch
   Research into “High” severity 25 Km/h pulse
    (EuroNCAP)
   Research into “Low” severity pulses (10, 16 Km/h)
   Research for EuroNCAP WAD group
   IIWPG Test program formulation for 2006 MY
   16 Km/h seat requests issued March 05
   16 Km/h tests to commence June 05
   2006 MY launch – November 2005 (International
    Launch – Thatcham/IIHS
WWW.Thatcham.org

				
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posted:8/9/2011
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