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HR-7-8GTR Head restraintsDynamic test procedure

Trigger-point in dynamic test procedure

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HR-7-8GTR Head RestraintsDynamic test procedure – trigger point

– full vehicle sled test (without wheels, fluids)

– synthetic sinusoidal pulse peak acceleration: 86 m/s² (corridor defined)max velocity (delta v): 17, 3 km/h ± 0,6 km/h

– 50th-percentile male Hybrid III test dummy (49 CFR § 572, Subpart E)

– angular rotation between head and torso 12°

– HIC15 500

FMVSS 202a provides a dynamic test procedure as compliance option for front outboard designated seating positions

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HR-7-8GTR Head RestraintsDynamic test procedure – trigger point

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HR-7-8GTR Head RestraintsDynamic test procedure – trigger point

Active head restraint system

– reducing of backset in case of rear end collision by moving head restraints front surface;

– energy store (e.g. preloaded spring, pyrotechnic actuator);

– Activation by control unit (e.g. airbag-control-unit)

– Activation dependant on algorithm which is implemented in control unit and is based on various sensor signals received in real world crash;

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HR-7-8GTR Head RestraintsDynamic test procedure – trigger point

Comparison of vehicle accelerations in test procedures concerning rear end collisions

– FMVSS 202a dynamic test;

– barrier test (with equivalent velocity change)

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HR-7-8GTR Head RestraintsDynamic test procedure – trigger point

Barrier test for rear end collision

Dynamic test with movable barrier to test for vehicle in rear end collisions. The barrier test shall cause a corresponding velocity change (energy) to the FMVSS 202a dynamic test; The impact speed of the barrier is vehicle specific– movable barrier

(longitudinal direction) impacts vehicle at standstill from rear;

– barrier weight 1400 kg;

– 10° angle of barrier to vehicle longitudinal axis;

– 40% offset;

– approx. 35 km/h barrier impact speed

(dependant on mass of struck vehicle);

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HR-7-8GTR Head RestraintsDynamic test procedure – trigger point

Comparison of sensed vehicle accelerationsA

ccele

rati

on [

m

/s²

]

Time [ s ]

barrier test

FMVSS 202a

Acceleration sensor signal at vehicle body (B-pillar position)

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HR-7-8GTR Head RestraintsDynamic test procedure – trigger point

Deployment of active head restraint

The software and data in the control units contain:

– plausibility checks of sensor signals;

– discrimination routines for crash severity;

The deployment algorithm of an active head restraint is contained in the control unit.(e.g. airbag control unit)

The deployment algorithm evaluates various sensor signals (e.g. linear acceleration; rotational acceleration, deformation)

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HR-7-8GTR Head RestraintsDynamic test procedure – trigger point

The active head restraint may not deploy if vehicle is subjected to a dynamic test according to FMVSS 202a.

The active head restraint will deploy if vehicle is subjected to a rear end collision with a velocity change of the vehicle of 17, 3 km/h.

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HR-7-8GTR Head RestraintsDynamic test procedure – trigger point

Proposal for active head restraints in dynamic test procedure

– Dynamic test procedure according to FMVSS 202a with battery installed and ignition “ON”;

(Airbag system operable)

– Usage of trigger point for active head restraints in dynamic test procedure according to FMVSS 202a

on request of the vehicle manufacturer;

– Vehicle specific trigger point according to manufacturer’s information;

– Manufacturer must provide data of a standardized barrier test (rear end collision) with energy level (delta v 17,3 km/h) of FMVSS 202a pulse;

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HR-7-8GTR Head RestraintsDynamic test procedure – trigger point

End of presentation

Thank you for your attention