GB 24550-2024Protection of motor vehicle for pedestrians in the event of a collision (English PDF)

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

4.3 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

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.

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.

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.

5.3.2.2 Sensors

5.3.3.2 Adult headform impactor 5.3.3.2.1 Structural dimensions The adult headform impactor shall be made of aluminum, homogeneous structure, spherical, with a diameter of 165 mm ± 1 mm and a mass of

0.1 kg, as shown in Figure

18.The moment of inertia relative to the axis passing through the center of mass and perpendicular to the impact direction shall be

0.010 kg·m2 ~

0.013 kg·m2. The center of mass of the headform impactor including the sensor shall be located at the geometric center of the ball, which has a deviation of ±5 mm. The ball is covered with a synthetic skin of

0.5 mm thick, covering at least half of the ball. 5.3.3.2.2 Sensor 5.3.3.2.3 First natural frequency The first natural frequency of the headform impactor shall be greater than 5000 Hz. shall be located on the midline of the upper bumper reference line and the lower bumper reference line, with a longitudinal deviation of ±10 mm; the lateral deviation of the vertical centerline of the impactor from the selected impact position shall be ±10 mm. The laboratory may also use multiple tests to prove that the test meets the accuracy requirements.

6.2 Test procedure for headform

6.2.1 Propulsion of headform impactor The headform impactor shall be in free flight at the moment of impact and shall comply with the impact velocity specified in

6.4.6 and the impact direction specified in

6.3.7 and 6.4.7.The impactor shall be released into free flight, at a certain distance from the vehicle. This distance shall ensure that the contact between the propulsion system and the impactor does not affect the test results when the impactor rebounds.

6.2.2 Measurement of impact velocity Measure the velocity of the headform impactor in free flight before impact according to the method specified in ISO 3784.The velocity measurement accuracy shall be ±

0.02 m/s. When determining the impact velocity of the impactor, consider all factors that may affect the impactor and calculate or measure the angle of the velocity vector at the time of impact.

6.2.3 Recording The acceleration-time history shall be recorded and the HIC calculated. Record the measurement points of the front structure of the vehicle. Record the test results according to ISO 6487.

6.2.4 Measurement points Select the positions that are likely to cause greater harm to pedestrians as measurement points in sequence. If the remaining test area is too small and the selected measurement points cannot ensure the minimum interval, the number of tests can be less than

9.The positions of the measurement points shall be recorded in the test report. When the vehicle is equipped with an active device to protect vulnerable road participants such as pedestrians, the measurement points shall be selected when the active device is not activated; the positions that are likely to cause greater harm to pedestrians when the active device is activated can be considered.

6.3 Child head form test procedure

6.3.1 The test shall be conducted in the child headform bonnet top test area and/or windscreen test area. For the rear end of the bonnet top test area, the head form impactor shall not contact the windscreen or A-pillar before impact. For the test in the windscreen test area, the head form impactor shall not directly contact the A-pillar, the front windscreen opaque area (excluding the interior rearview mirror installation area), the wiper groove area.

6.3.2 At least 9 child head form tests shall be conducted. Three tests shall be conducted in the middle and two side test areas of the third of bonnet upper area. The test positions shall be selected from different structural types of positions, that are most likely to cause head injuries. If the vehicle structure permits, at least one child head form test shall be conducted in the windscreen head form test area. Each time the windscreen area head form test is conducted, a new, undamaged glass shall be used.

6.3.3 The distance between the measuring points shall be no less than 165 mm. This distance is determined by tightening a soft ruler along the outer surface of the vehicle.

6.3.4 Positions outside the test area that cause more serious secondary injuries shall not be selected as measuring points.

6.3.5 The lateral and longitudinal impact deviations of the child head form test shall be within ±10 mm. This deviation shall be measured along the outer surface of the bonnet or windscreen. The laboratory may also use multiple tests to prove that the test meets the accuracy requirements.

6.3.6 The speed of the child head form impactor during impact shall be

0.2 m/s.

6.3.7 The impact direction during the test shall be in the longitudinal vertical plane of the vehicle; the test impact angle relative to the horizontal plane shall be 50o ± 2o; it shall be downward and backward relative to the front structure of the vehicle.

6.3.8 During the windscreen child headform test, when the child headform impactor does not directly or indirectly contact the vehicle internal structure or other structures below the windscreen and the HIC is greater than the corresponding area limit, meanwhile atypical windscreen breakage occurs, the manufacturer may repeat the test. The test may be repeated up to 3 times; the situation shall be recorded in the test report.

6.4 Test procedure for adult headform

6.4.1 The test shall be conducted in the bonnet top test area and/or windscreen test area of the adult headform. For the rear end of the bonnet top test area, the headform impactor shall not contact the windscreen or A-pillar before impact. For the test in the windscreen test area, the head impactor shall not directly contact the A-pillar, the opaque area of the windscreen (excluding the interior rearview mirror installation area), the wiper groove area.

6.4.2 At least 9 adult head tests shall be conducted. Three tests shall be conducted in the middle and two side test areas of the third of hood top area. The test positions shall be selected from different vehicle body structure types, that are most likely to cause head injuries. If the vehicle structure permits, at least 1 adult headform test shall be conducted in the windscreen headform test area. For each windscreen area headform test, it shall use new, undamaged glass.

6.4.3 The distance between the measuring points shall be no less than 165 mm; this distance is determined by tensioning a soft ruler along the outer surface of the vehicle.

6.4.4 Locations that cause more serious secondary injuries outside the test area shall not be selected as measuring points.

6.4.5 The lateral and longitudinal impact deviations of the adult headform test shall be within ±10 mm. This deviation shall be measured along the outer surface of the bonnet or windscreen. The laboratory may also use multiple tests to prove that the test meets the accuracy requirements.

6.4.6 The speed of the adult headform impactor during impact shall be

0.2 m/s.

6.4.7 The impact direction during the test shall be in the longitudinal vertical plane of the vehicle; the test impact angle relative to the horizontal plane shall be 65o ± 2o; it shall be downward and backward relative to the front structure of the vehicle.

6.4.8 During the windscreen adult headform test, when the adult headform impactor does not directly or indirectly contact the vehicle internal structure or other structures below the windscreen and the HIC is greater than the corresponding area limit, meanwhile atypical windscreen breakage occurs, the manufacturer may repeat the test. The test can be repeated up to 3 times; the situation shall be recorded in the test report.