Table of specifications

This project is for the design, fabrication, and testing of a side under ride guard w/ aerodynamic fairing system. According to the NHTSA, approximately 226 people die annually due to side under ride and 98% of collisions with a trailer result in at least one fatality. These alarming statistics, in conjunction with a lack of safety requirements for trailers, led to the need for this project.

All trailers have a maximum allowable weight while traveling on the interstate highway system in the United States; this dictates load capacity and therefore effects the value of each truck load on the road. Any increase in the weight of the trailer will decrease the hauling capacity of the trailer and will therefore reduce the overall value of each truck load. This potential loss of value is a significant deterrent to the installation of any under ride guard system. To compensate for the inherent loss of hauling capacity an aerodynamic fairing will be incorporated into the design; significant savings on fuel cost will offset the operational cost of employing the guard system and will also be viewed as a positive, environmentally friendly act by the public.

 

The Specifics

A side under ride guard will be a life saving device and as such the specifications, given by the sponsor, are for worst-case scenarios. An average mid-size vehicle weighs approximately 3500lbs and a "light duty" vehicle can weigh up to 6000lbs. This definition of "light duty" vehicle will be used in the design as it includes a wide range of vehicles from sedans to full size pickup trucks and vans. A maximum speed of 35mph and an impulse time of 200ms will also be used.
To reduce the complexity of a structural analysis under dynamic loading conditions a static load equal to double the dynamic load will be applied (safety factor N=2). This design is modular such that, for any impact scenario, the force of impact will be distributed among no less than two guard structures. This equates to a static load of the same magnitude as a dynamic load for which we can use during analysis.
The aerodynamic fairing will mount to the guard structure and will not be designed to withstand the forces of impact; the fairing is to be replaceable.

FAMU-FSU College of Engineering

Side Underride Guard w/ Aerodynamic Fairing - Senior Design Fall 2010—Spring 2011

Project Description

Team 11