Criteria in the rule making process

1)      Head protection

2)      Chest protection

3)      Neck injury

Head protection

•      HPC (Head protection criteria) for United State or HIC (Head injury criteria) for Europe

•      Used to assess safety related to vehicles, personal protective gear, and sport equipment

•      The head injury criterion (HIC₃₆) or (HIC₁₅) shall be determined using the at the center of gravity of the dummy head

 

where, t1          = initial times

            t2           = final times

            ar          =  acceleration of gravity

***the value should not exceed 1000 or 700

Head protection figure:

•      At a HIC of 1000, one in six people will suffer a life-threatening injury to their brain

•      More accurately :

•      HIC of 700 is estimated to represent a 5% risk of a severe injury.

Chest protection

VC = viscous criteria <1m/sec

Compressive deflection of the sternum

relative to the spine shall not exceed

76 mm (3 in.).

·        

Lateral rip deflection <42mm (1.65 in.)

Compressive deflection of the

                          sternum relative to the spine shall

                          not exceed 63 mm (2.5 in.).

Compressive deflection of the

                          sternum relative to the spine shall

                          not exceed 50 mm (2 in.).

                          (European requirement).

Neck injury

When measuring neck injury, each of the following criteria shall be met:

1. The shear force (F_x), axial force (F_z), and bending moment (M_y) shall be measured by the dummy upper neck load cell for the duration of the crash event as specified.
2. During the event, the axial force (F_z) can be either in tension or compression, while the occipital condyle bending moment (M_ocy) can be either in flexion or extension.
3. This results in four possible loading conditions for N_ij :
1.                 -  tension-extension (N_te),

   
   
                             -  tension-flexion (N_tf),
                             -  compression-extension (N_ce)
                             -  compression-flexion (N_cf)
   
   
    N_ij = (F_z/F_zc) + (M_ocy/ M_yc)
   
   
   where,  F_z                    = axial force
               F_zc              = axial force in compression or tension
               M_ocy            = occipital condyle bending moment
               M_yc              = occipital condyle bending moment
                                  when a flexion moment exists at the occipital  condyle
   
   
   ***At each point in time, only one of the four loading conditions occurs and None of the four N_ij values shall exceed 1.0 at any time during the event.
                           
     F_zc       = 6806 N (1530 lbf) when Fz is in tension
     F_zc       = 6160 N (1385 lbf) when Fz is in compression
     M_yc     = 310 Nm (229 lbf-ft) when a flexion moment exists
                    at the occipital  condyle
     M_yc     = 135 Nm (100 lbf-ft) when a extension moment
                    exists at the occipital condyle
   
   
   Peak tension force (F_z), measured at the upper neck load cell, shall not exceed 4170 N (937 lbf) at any time.
   
   
   Peak compression force (F_z), measured at the upper neck load cell, shall not exceed 4100 N (937 lbf) at any time.
   
   
   Neck rearward torsion moment should not exceed 57 Nm(requirement for Europe).
   
   
   
   
   
   
   
   
   
   
   
   
   edited by: Ahmad Amirul Ariff bin Arrifin (54268111042)