Automobile Impacts with Small Signs

摘要

The report examines the physics of low-speed and high-speed impacts of an automobile with a small sign. The vehicle parameters that are important in the impact and post-impact or runout phase are defined. Small signs are classified as either breakaway or ridedown depending on their mode of failure. The emphasis of the report is on small signs with a ridedown type of failure mode. Two models for this type of behavior are defined. The low-speed model addresses both the inertial effects based on the sign and post weight and the importance of the plastic hinge formed in the post at the groundline. The high-speed model is more complex and is implemented in a BASIC computer program called the Vehicle/Sign Impact Model (VSIM). The results of the two models are used to define the important vehicle characteristics for impact conditions. Based on this information, the requirements for a reusable surrogate vehicle (bogie) for use at the Federal Outdoor Impact Laboratory (FOIL) are defined.