Structural optimization and running dynamic evaluation of a railway bogie frame

Nowadays, rolling stock manufacturers work to reduce the environmental impact of railway vehicles, that are one of the most important solution for mass transport over the world, also for emerging countries. Innovation of the structural design and traction source represent the two main points of interest. Focusing on the first one, vehicles lightweight design allows to reduce the energy required during their operation conditions. With the objective to reach this ambitious result, structural optimization process can represent an effective support for the development of innovative components in railway field. However, the current standards for the design of carbody and bogie frame, do not defined a role for this type of approach. Available literature illustrates that not many studies about optimization processes, especially applied on railway vehicles bogie frame, have been carried out. A size optimization and a material selection method have been combined to test an electrical multiple unit (EMU) carbody. Topology optimization and composite materials have been combined to redesign a railway anchor bracket. Running comfort condition must be carefully evaluated, ensuring the decouplment of the carbody from bogie instability motion, as well as from the suspension frequencies. Bogie is the most critical component of a railway vehicle and over the years it has undergone only minor changes. In order to fill this gap, authors have proposed a first topological optimization approach, combined with the reference European standard for bogie structural requirements. The benchmark aims to reduce the mass structure possibly ensuring the mechanical performance of the system, including static, dynamic and fatigue evaluations. In addition, a multibody analysis was conducted to compare the optimized solution and the original one in terms of running dynamic. The procedure was tested on a bogie frame designed for a light rail vehicle.