Impact energy test vehicle

Plastics products are most likely to fail in a brittle manner under impact conditions, both due to strain rate effects and because large forces can be generated by low energy impacts on stiff structures. A variety of impact tests are used. Usually a weight falls from a height of the order of Im to hit the test specimen with a velocity of about 5ms . This simulates the strain rates that occur when a product is dropped about a metre, but not the higher strain rates in vehicle collisions or ballistic impacts. The uses and limitations of three types of impact tests will be discussed. 

Similarly, side impact protection is quite limited the very small space between a vehicle occupant and side intrusion severely limits the vehicle designers options for absorbing kinetic energy before it impacts on the occupant. It is worth noting that the safety design rule for crash testing for side impact occupant protection requires a test at 50 km/h. Actual crashes at intersections on higher-speed roads often involve impact speeds well above this level. 

AU automotive components that will be used in areas subject to potential vehicle impact require topcoats that involve highly flexible clearcoats. This is needed to avoid a drastic reduction of energy absorption upon impact. In instrumented impact tests, elastomeric-modified PC blends perform giving excellent results as high as 100 Nm at 23°C and show very little loss down to 40°C. If the specific requirement for the coated part is, for example, that the performance shall be more or less maintained without any brittle failure at -20°C, the flexible nature of the clearcoat can be adjusted accordingly using the instrumented impact method (2). More often however, the performance specification is defined according to the OEM requirement for a complete bumper system. 

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