Multi-body dynamic modelling and simulations for train crashworthiness design analysis

One of the most important issues for rail passenger vehicles is on occupant safety through vehicle crashworthiness. Crashworthiness, in terms of rail vehicle designs, is the capability to dissipate the crash energy in such a controlled fashion that the overall damage is inconsequential to passenger space. A case study on a popular city passenger train has been conducted using a multi-body formulation of a three-dimensional, non-linear rigid body dynamic train model. The simulated crash scenario details a one to eight vehicle train in a front-on collision onto a fixed block. The crashworthiness is measured in terms of the degree of impact energy absorption, vehicle deceleration, and passenger injury criteria. The results showed that in a single vehicle, the crash energy management systems (CEMS) adequately compensated for the effects of impact at a crash speed of 44.5 km/h and below. At higher speeds, it is projected that the energy crush zones will need significant structural increases in both its crush length and crush force. An increase in the crush length is normally preferred over the crush force so as to maintain the longitudinal deceleration gradient within a tolerable range to ensure passenger safety. The benefits of computational modelling and simulations should not be underestimated as it allows for a thorough appreciation of a sound appreciation of the crashworthy structures and energy absorbers within any rail vehicle during the initial periods of the design process.