An innovative numerical approach for railway rolling noise forecast

In recent years there has been a growing worldwide development of rail transport, mainly due to technological innovations both on armaments and on rail vehicles. Such technological issue focused almost parallel on two main fronts: on one hand the performance enhancement and on the other side the internal comfort. This technology advancement has been driven mainly by the need to move goods and passengers over long distances in a short time, making it the safest transportation system in the world thanks also to the latest monitoring systems, of which European Community is undoubtedly one of the major leaders. The passenger transport has introduced problems related to comfort: traveling so fast is the main goal so long as it is comfortable and safe. One of the requirements that mostly turned out to be significant and sometimes more difficult to satisfy is that regarding acoustic comfort and environmental impact. As known, the regulations become with the passage of time more and more stringent, and every company that wants to operate in this area is required to respect them. The acoustic comfort improvement implies the intervention as much as possible focused on noise sources, which in this case are constituted by: electric motor, pantograph, wheel-rail contact. In such research framework, the authors focused on determination of a simple, but at the same time reliable, method for radiated sound power assessment in the wheel-rail contact due to combined wheel-rail roughness in order to reduce the environmental impact of this type of transmission system. Targeted analysis were implemented in an efficient numerical investigation in MSC NASTRAN® and ACTRAN® environments providing the necessary vibro-acoustic parameters as input data for the further definition of the wheel-rail interaction force by a MATLAB® customized tool, once known the roughness profile.