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GB 24550-2024: Protection of motor vehicle for pedestrians in the event of a collision
GB 24550-2024
GB
NATIONAL STANDARD OF THE
PEOPLE?€?S REPUBLIC OF CHINA
ICS 43.020
CCS T 09
Replacing GB/T 24550-2009
Protection of motor vehicle for pedestrians in the event of a
collision
ISSUED ON: MAY 28, 2024
IMPLEMENTED ON: JANUARY 01, 2025
Issued by: State Administration for Market Regulation;
National Standardization Administration.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Terms and definitions ... 4
4 Technical requirements ... 18
5 Test requirements ... 21
6 Test procedure ... 31
7 Calibration of impactor ... 38
8 Determination of the same type ... 51
9 Implementation of the standard ... 51
Protection of motor vehicle for pedestrians in the event of a
collision
1 Scope
This document specifies the technical requirements, test requirements, test procedures,
calibration of impactors, same type determination, implementation of standards for
protection of motor vehicle for pedestrians in the event of a collision.
This document is applicable to categories M1 and N1 vehicles. It does not include the
category M1 vehicles, which have a maximum total mass greater than 2500 kg, where
the driver's seat R point is in front of the front axle?€?s center transverse plane or the
horizontal distance between the driver's seat R point and the front axle center transverse
plane is not greater than 1100 mm; nor does it include category N1 vehicles with a
driver's seat R point in front of the front axle?€?s center transverse plane or the horizontal
distance between the driver's seat R point and the front axle?€?s center transverse plane is
not greater than 1100 mm.
2 Normative references
The contents of the following documents constitute essential clauses of this document
through normative references in the text. Among them, for dated references, only the
version corresponding to that date applies to this document; for undated references, the
latest version (including all amendments) applies to this document.
GB 15084 Motor vehicles - Devices for indirect vision - Requirements of
performance and installation
ISO 3784 Road vehicles - Measurement of impact velocity in collision test
ISO 6487 Road vehicles - Measurement techniques in impact tests - Instrumentation
3 Terms and definitions
The terms and definitions defined in GB 15084 and the following terms and definitions
apply to this document.
3.1
Normal ride attitude
The state of the vehicle when it is in normal driving at a speed of 40 km/h.
Note 1: The vehicle in the state of full vehicle curb weight is placed on a horizontal surface;
the counterweights simulating the driver and one passenger are placed on the driver's seat
and the front passenger seat, respectively. The front seat is placed in the middle position of
the front and rear travel or the first locking position after the middle position. The tire
pressure is the tire pressure specified by the manufacturer; the front wheels are in the straight
driving position; the vehicle suspension is in the state specified by the manufacturer.
Note 2: The curb weight of the vehicle is the weight of the vehicle with the body and all the
assembly equipment, electronic and auxiliary equipment (such as fluids, tools, fire
extinguishers, standard spare parts, wheel chocks, spare tires, etc.) required to ensure the
normal operation of the vehicle; the fuel tank (if any) is filled with fuel accounting for 90%
of the total capacity; other fluids are added to the capacity specified by the manufacturer.
The counterweight mass of the driver and passenger is 75 kg, consisting of 68 kg of
simulated human mass on the seat and 7 kg of simulated luggage mass, which is placed in
the rear luggage compartment (or placed in the front luggage compartment).
3.2
Ground reference plane
The horizontal plane passing through the lowest contact point of all tires of the
vehicle in the normal ride attitude of the vehicle.
Note: This plane is real or imaginary. If the vehicle is stationary on the ground, it is on the
same plane as the ground level; if the vehicle is lifted from the ground to obtain additional
clearance under the bumper, it is above the ground level.
3.3
Front structure
All front end external structures of the vehicle, excluding the front windscreen upper
crossbeam, A-pillar, structure behind the A-pillar.
Note: It includes but not limited to bumper, bonnet, fender, water channel, wiper shaft, front
windscreen, front windscreen lower beam, etc.
3.4
Bumper
External component located at the front of the vehicle with decorative, absorbing
and mitigating impact functions.
Note: It includes all structures and accessories that protect the vehicle in a low-speed frontal
collision.
3.28
Assessment interval
The specific time period -- from the moment when the lower leg form impactor first
contacts the vehicle to the moment when all leg bone bending moment curves of the
lower leg type reach the maximum value (exceeding 15 N??m) for the first time and
then drop to zero.
Note 1: The assessment interval of ligament extension is the same as that of leg bone
bending moment. If there is a leg bone bending moment curve that does not intersect with
zero during the time period when all leg bone bending moments intersect with zero, all leg
bone bending moment time history curves are moved up or down, until all leg bone bending
moment curves intersect with zero for the first time. The movement of the leg bone bending
moment time history curve is only used to determine the assessment interval.
Note 2: If the leg bone bending moment curves do not drop to zero at the same time, a
specific time period -- from the first contact between the lower leg form impactor and the
vehicle to the first intersection of all leg bone bending moment curves -- is selected; the
movement of the leg bone bending moment time history curve is only used to determine the
assessment interval.
3.29
Atypical windscreen fracture behavior
The fracture phenomenon that occurs during the test of the headform impactor
hitting the windscreen.
Note: Within the first 4 ms after the first contact between the headform and the windscreen,
the absolute value of the minimum value of the headform acceleration and the time
derivative is not greater than 180 g/ms; or the windscreen remains unbroken for more than
1 ms.
4 Technical requirements
4.1 Leg form test requirements
4.1.1 General
Vehicles with a lower bumper height of less than 425 mm shall comply with the
requirements of 4.1.2.
Vehicles with a lower bumper height of not less than 425 mm but less than 500 mm
shall comply with the requirements of 4.1.2 or 4.1.3.
Vehicles with a lower bumper height of not less than 500 mm shall comply with the
of each area shall not be greater than 1000; the HIC of the remaining area shall not be
greater than 1700.
4.3 Test requirements for vehicles with variable height
If the vehicle is equipped with a system that can change the body height during driving
on urban roads, meanwhile the change in the front axle height is greater than 25 mm
when the driving speed is within 25 km/h ~ 40 km/h, the measurement points of relevant
test area caused by the change in body height shall also comply with the provisions of
4.1 and 4.2. The impact speed of the impactor is the speed specified in Chapter 6 or the
driving speed corresponding to the vehicle height (the speed deviation is ??0.2 m/s).
When the driving speed corresponding to the vehicle height is selected, the ratio -- of
the headform impactor speed to the vehicle driving speed -- is 0.9, meanwhile the
headform impactor speed is not greater than 9.7 m/s ?? 0.2 m/s.
4.4 Division of headform test area
4.4.1 The manufacturer shall determine the bonnet top test area and the front windscreen
test area, which has a HIC not greater than 1000 (HIC 1000 area) or not greater than
1700 (HIC 1700 area) (see Figure 12).
4.4.2 The bonnet top test area and the front windscreen test area, as well as the HIC
1000 area and the HIC 1700 area, shall be determined based on the top view of the
vehicle provided by the manufacturer. The manufacturer shall provide the necessary x,
y coordinate values, to mark the test area on the actual vehicle, taking into account the
vehicle's shape in the z direction.
4.4.3 The HIC 1000 area and the HIC 1700 area can be composed of several parts; the
number of components is not limited. The bonnet top test area and the front windscreen
test area are determined by measuring points. The calculation of the bonnet top test area
and the front windscreen test area, as well as the HIC1000 area and HIC 1700 area
surface, shall be based on the top view of the hood and the front windscreen, that is,
based on the top view of the vehicle provided by the manufacturer.
angle relative to the horizontal plane of not more than 1%.
5.2 Vehicle preparation
5.2.1 When determining the vehicle reference line and test area, the vehicle shall be in
a normal ride attitude. If the vehicle is equipped with a trademark, logo or other
structure that can bend or retract, a load of not more than 100 N shall be applied to make
it bend or retract. Any part of the vehicle that can change shape or position, except for
the suspension parts of the vehicle, shall be in the retracted position. Devices used to
protect vulnerable road participants such as pedestrians shall be in the inactive state.
5.2.2 For a complete vehicle or vehicle body, the test shall be conducted after debugging
under the following conditions.
a) The vehicle shall be in a normal ride attitude and firmly placed on a support frame
or parked on a horizontal plane with the parking brake engaged.
b) The vehicle body shall include all parts of the vehicle's front structure, all parts
under the bonnet, all parts behind the windscreen that may be related to
pedestrians and other vulnerable road participants in a frontal collision, so as to
reflect the performance and interaction of all the participating parts on the vehicle.
The vehicle body shall be firmly fixed in the normal ride attitude of the vehicle.
c) Holes, surfaces, marks, identification signs on the vehicle body can be used as
vehicle reference marks specified by the vehicle manufacturer, in the normal ride
attitude of the vehicle. The height of the reference mark is the vertical height
relative to the ground reference plane. When the height of the reference mark is
within ??25 mm of the design height in the normal ride attitude of the vehicle,
adjust the vehicle to the design height position for testing.
5.2.3 In the event of a collision with a vehicle, all devices designed to protect
pedestrians and other vulnerable road participants can be tested in the activated state, if
the manufacturer provides materials to prove the effectiveness of the device.
5.2.4 In addition to devices used to protect vulnerable road participants such as
pedestrians, for vehicle parts that can change shape or position, and parts with more
than one fixed shape or position, the vehicle shall be tested in each shape or position.
5.3 Provisions for test impactors
5.3.1 Lower leg form impactor
5.3.1.1 Structural dimensions
5.3.1.1.1 The lower leg form impactor shall consist of skin, muscle, femur, tibia, knee.
The outer dimensions are as shown in Figure 13. The total mass of the lower leg form
impactor is 13.2 kg ?? 0.4 kg. Brackets, pulleys and other devices that connect the
guiding components that are an important part of the impactor during the impact, shall
be 9.5 kg ?? 0.1 kg.
5.3.2.1.3 The total mass (excluding foam and skin) of the front parts of the upper leg
form impactor and other parts in front of the load sensor assembly, plus the parts in
front of the starting element in the load sensor assembly, is 1.95 kg ?? 0.05 kg.
5.3.2.1.4 The upper leg form impactor shall be mounted on the propulsion system
through a torque-limiting connector and shall be insensitive to non-axial loads. When
in contact with the vehicle, the impactor shall be prevented from moving and rotating
in other directions, to ensure that the impactor moves in the specified impact direction.
5.3.2.1.5 When adjusting the torque-limiting connector, it shall be ensured that the
longitudinal axis of the front part remains within 90?? ?? 2?? during impact, the friction
torque of the connector is 675 N??m ?? 25 N??m.
5.3.2.1.6 The center of mass of the impactor parts before the torque-limiting connector,
including all weights, shall be within ?? 10 mm of the longitudinal centerline of the
impactor.
5.3.2.1.7 The distance between the center lines of the load cells is 310 mm ?? 1 mm; the
diameter of the front part is 50 mm ?? 1 mm.
5.3.2.1.8 For each test, the impactor shall be equipped with two new 25 mm thick CF-
45 type foam muscles or equivalent; the foam muscles shall be made of the same
material as the dynamic calibration test. The skin is a 1.5 mm thick fiber reinforced
rubber layer. The total mass of the foam muscle and rubber skin is 0.6 kg ?? 0.1 kg,
excluding all fixings and mountings used to connect the rear edge of the rubber skin to
the rear part. The foam muscle and rubber skin are folded backwards; the rubber skin
is fixed to the rear part by pads, so that the sides of the rubber skin remain parallel. The
size and shape of the foam muscle shall ensure that there is sufficient clearance between
the foam muscle and the parts behind the front part, to avoid the transfer of large loads
between the foam muscle and these parts.
5.3.2.2 Sensors
5.3.2.2.1 Two load sensors measure the forces applied to the two ends of the upper leg
form impactor respectively; the strain sensors measure the bending moment at three
positions as shown in Figure 16. The sensors at each position use a separate
measurement channel. The strain sensors shall be installed behind the front part of the
impactor. The two outer strain sensors are located at 50 mm ?? 1 mm from the
longitudinal centerline of the impactor; the middle strain sensor is located on the
longitudinal centerline with a...