This concept exploration project assessed the potential of Solid Ejection Material (SEM) crash energy absorption technology for high-speed rail applications. A basic SEM model consists of an impact piston inside a shock housing, and the end of the piston inside the housing is in contact with a ductile or yieldable solid (polymer). The housing contains an ejection groove or ejection ports. If the piston is impacted, such as in a collision, the other end of the piston forces the ductile or yieldable solid through the ejection groove or ports, thereby absorbing much of the crash energy. The specific application of this proposed technology was the development and testing of an SEM shock track for mounting seats in rail passenger cars (Figure 1). In the event of, for example, a head-end or rear-end collision, the SEM shock track mounting would provide controlled acceleration and deceleration of the seat assembly. Although rail passengers do not wear seat restraints, the controlled acceleration-deceleration would provide some protection to passengers thrown into the back of the seat ahead in the event of a head-end collision. In the event of a rear-end collision, the shock track would absorb much of the energy forcing the seats to the rear. The shock track would also reduce the likelihood of the breakaway of seat assemblies.
Project tasks included the design and fabrication of a prototype system, installation of that system on seats installed in a 4-wheel test vehicle, and controlled impacts of the test vehicle into a barrier. The test vehicle was equipped with instrumented test dummies to record impact forces that would be experienced by rail passengers in a train collision.
