| Popis: |
The homologation of railway vehicles in Europe is ruled by EN-14363. It defines testing scenarios, experimental setups, data post-processing procedures and the limit values to be respected by a number of different parameters, mainly associated with vehicle safety. The key role of the entire homologation process is represented by the instrumentation setup and the measurement chain, which are essential in getting accurate parameters which has to represent physical quantities with only marginal uncertainties. Among all the measured parameters, contact forces between the train wheelset and rails retain a significant importance in the Normal Method, requested by the standard. Since, unlike other physical quantities (e.g. accelerations or displacements), contact forces cannot be measured directly during train rides, it is nodal to have a consistent and coherent theoretical model to correlate measurable quantities such as strains and displacements measured on wheelsets with real contact forces. Following this approach, it is crucial to have a robust and reliable measurement chain able to acquire right values of those quantities and transfer them on the elaboration unit. The scope of this paper is hence to present a brief overview of this measurement chain, of the solutions adopted with its points of strength and the encountered issues. In conclusion, future developments of the system will be briefly hinted at. |
