Mechanical & Materials Engineering, Department of


Date of this Version



A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science, Major: Mechanical Engineering, Under the Supervision of Professor John D. Reid. Lincoln, Nebraska: December, 2011

Copyright (c) 2011 Curt Lee Meyer


A new diaphragm and dual guide rail system was designed for use in a crash cushion for high-speed race tracks. These structural components were designed to provide sufficient lateral support to redirect impacting vehicles and compress the energy-absorbing elements of the crash cushion. The primary design criteria stated that the diaphragm/guide rail system should be capable of withstanding a 100-kip lateral impact load. The guide rail was to be configured in order to not require replacement after a design impact event. Initial design and modeling resulted in two candidates for guide rail sections which were evaluated during physical testing. The better of the two candidates was then paired with a prototype diaphragm and subjected to dynamic testing. The first prototype was found to develop a maximum resistive force of 175 kips, and the diaphragm guide rail absorbed a total of 822 kip-in. of energy but sustained significant guide rail damage. An extensive computer modeling effort was initiated to optimize both the diaphragm and the guide rails. The structural capacity of the optimized prototype diaphragm and guide rail system was verified through a dynamic bogie test. The second prototype weighed 55 lbs less, developed a maximum resistive force of 212 kips, and absorbed a total of 929 kip-in. of energy, resulting in a guide rail permanent deflection of 1/16 in. Meeting all design requirements, the second prototype is recommended for use in the continued development of the crash cushion for high-speed race track applications.

Adviser: John D. Reid