SEPTEMBER 7--CEDIP Infrared Systems (Croissy-Beaubourg, France;
www.cedip-infrared.com) has announced the availability of a study undertaken in conjunction with CNRS-EUDIL (Lille, France) describing the use of its high-performance JADE MW-IR camera to characterize suitable brake-disk materials for the French TGV high-speed train. The goal of these tests was to determine the temperature distribution at the surface of the disk during the breaking phase and also to determine the performance of various materials cladding configuration that are used as disk materials.
When the TGV train has to brake from full speed to full stop, the dissipated energy is close to 15 MJ, resulting in the induction of high temperatures at the disk break surface. The materials for brake disks must be designed to efficiently dissipate this huge amount of heat. Measurement of the temperature distribution at the disk surface was essential to validate the design of the material cladding that constitutes the disk surface. To be representative of the heat dissipation, the temperature measurement must be made while the disk is spinning and during the breaking phase.
A JADE MWIR camera operating in the 3--5-μm waveband was used to measure the temperature distribution at a 200-Hz frame rate. To freeze the motion per frame, the integration time was reduced down to 10 μs. Since the JADE cameras incorporate high-quantum-efficiency infrared focal-plane arrays, they preserved the required high sensitivity even under these demanding conditions. The brake disks under test were mounted into an experimental setup designed to reproduce the speed and location encountered during the breaking phase. The camera was mounted to observe approximately half of the disk surface.
The results obtained have permitted CNRS-EUDIL to determine the most appropriate type of brake cladding both in terms of shape and type of materials used. Further information regarding this study and the JADE MW-IR camera are available from CEDIP Infrared Systems.
