NewRail

Projects

ALJOIN

Aluminium alloys are now in widespread use for rail vehicle construction. However, in recent collisions involving seam-welded aluminium rail coaches, it has been observed that some of the longitudinal seam welds have fractured for several metres beyond the zone of severe damage, the panels themselves generally being intact without significant distortion. Designers need data to assess this fracture phenomenon and be able to take appropriate measures. In addition, there is a need for innovation in the use of joining techniques and joint design concepts to improve the performance of aluminium vehicles under crash conditions. ALJOIN studied and evaluated the use of alternative grades of aluminium alloys to improve the crashworthiness of rail vehicles. ALJOIN also appraised the use of alternative non-fusion welding techniques for rail coaches, such as friction stir welding (FSW). Performance criteria for aluminium welding in new generations of rail vehicles were defined and samples were tested under both static and dynamic loading. These tests were conducted in conjunction with finite element simulations to aid an analytical approach to the modelling of crashworthy aluminium rail vehicles. A further innovative output from the work was the definition of a method for assessing crashworthiness in the context of welded aluminium joints and structures, as this aspect is not fully covered by existing design codes, especially as far as energy absorption and the effects of strain localisation on the structural behaviour of the joints are concerned.