TEST DEVICES

•       Simulation of parts of the human body and the complete human is necessary to test vehicle components and the vehicle.

•       Although professional investigations with human volunteers have been used, these can be performed only in situations where no injuries occur.

•       It can be stated that the level of the crash test should not be high enough to cause injuries.

•       In a lateral car-to-car crash with an impact speed of 34 km/h (21mph), this corresponds to a change in velocity of 17 km/h (10.5 mph), restrained by a standard three-point seat belt.

•       The following observations could be made:

•       The pulse frequency jumped from 105 to 175 during the impact phase, a small concussion could be observed, and muscle pain occurred over the whole body.

•       This clearly was below the injury limit, but slightly higher change of velocity already might have created minor injuries.

•       For the development of vehicles and vehicle components, engineers must have reliable and reproducible results.

•       Likewise, the test calculations must be performed in areas where injuries can occur. This automatically prohibits the use of human volunteers as test specimens.

•       For this reason, many test devices are available and are used for the development and evaluation of production cars.

Body Part Test Devices

• For vehicles, component test devices are used in the following areas:

•       The simplest equipment is a measurement device to control the radius of the outer parts of the vehicle. It must be greater than 3.2 mm (0.125 in.).

•       Another measurement is done by a head form, which defines the impact zone at the dashboard and the vehicle interior.

Head Impact

• Figure 1 shows a head impact test device that is used to measure the g-level during an impact of the reduced pendulum mass of 6.8 kg (15 lb).
• The head impact form can be equipped with a three-dimensional accelerometer. It also can be used by attaching it with glue to foil, which shows the surface pressure if contact with a vehicle interior part occurs during the crash.
• The head form also could be used in a free-flying mode to check the deceleration level of the head form during contact with the vehicle interior. The requirements are defined in FMVSS 201 and SAE J 921. 

Torso Impact

• To check the steering wheel and assembly unit, a body of 36 kg (79 lb) in accordance with SAE 944 is used.
• The impact speed is 24 km/h (15 mph), and the test device represents a torso of a 50% male, as shown in Figure 2.
• Although the legal requirements are somewhat higher, most automobile manufacturers are designing their cars with values below 8000 N.

Pedestrian Accident Simulation Tests

• The safety of pedestrians is a key issue in several regions of the world. In discussions, the following test devices are proposed:

•       Child head form, 2.5 kg, 130-mm diameter (5.5 lb,

•        5.1-in.diameter

•       Adult head form, 4.8 kg, 165-mm diameter (10.5 

•        lb, 6.5-in diameter)

•       Hip impactor

•       Leg impactor 

 

 

• Case A: it is the more frequent trajectory in accident at low speed (= 20 km/h).
• Case B: it is the second more diffuse trajectory typology, the pedestrian barycentre is lower than bumper, so that it is typical of accidents involving children or persons having mean � low stature.
• Case C: it occurs when the vehicle impacts the pedestrian and slows down quickly. The pedestrian is load up the bonnet and is projected toward the windscreen or toward a vehicle side; then it falls and slides on the ground, until the stop. In this case the pedestrian assumes a speed forward greater than one of the vehicle in braking.
• Case D: this trajectory occurs in both the case of vehicle in braking or not; in this condition the vehicle goes with a speed equal to 40 km/h about, that is a very high speed for this type of accident. The pedestrian is struck near to the vehicle side and is loaded up the bonnet to be catapulted.
• Case E: the trajectory described by the crashed pedestrian is similar to the previous. It occurs when a pedestrian, with a gravity centre very higher than the bumper, is lift in aria due to the combined effect of the impact velocity and of the vehicle shape, when the vehicle accelerates after the impact or when the vehicle, having high speed (45�60 km/h), does not slow down.

• To design the vehicle front, in order to result less dangerous for the pedestrian, the very stiff parts are limited, reducing the thickness of the lateral bundles of the bonnet; the front is constructed without very acute angles, bonnet natural position is not very high and the mean length is not too reduced. The geometrical and mass characteristics of the vehicle are the following:
• wheelbase 2510 mm
• track 1510 mm
• mass 1200 kg
• max length 4030 mm
• max width 1690 mm
• max height 1490 mm 

Muhd Fadhli Bin Razak
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