Digital modelling for braking systems that resist super cold climatic conditions

Modelling techniques are largely widespread in aeronautics and the automobile sectors, enabling design engineers to gain considerably in time and efficiency as new equipment is being developed. In the framework of an R&D programme supported financially by the Picardie Region, the UTC Chair of Hydraulics and Mechatronics has set made an agreement to co-operate with an industrialist to design a digital simulator to develop a new braking system able to resist super-cold climatic conditions.

Digital modelling for braking systems that resist super cold climatic conditions

Occasionally, we see temperatures going down as far as -50°C ... and sometimes rising to over +40°C. Coping with such extreme variations in temperature calls for very close attention, to be paid to certain sensitive system parts of the braking system. Correct functioning and reliability of pneumatic equipment depend to a large extent on the quality of the seals to ensure transmission of adequate pressure levels. Equipment manufacturers specialized in railroad transportation are especially interested in new design techniques that potentially reduce costs and lead-times in development for the purpose of proposing a specific range of brake systems for the Canadian, Chinese and Russian markets.

Considerable industrial stakes

Project SIM-Brake was launched in 2014 in the framework of the Picardie Region IndustriLAB programmes with the dual objective to master those component parts that are temperature sensitive and to draw up robust methodology to pursue development plans. "Research scientists at UTC have been given the mission to deliver an accurate representation of hydraulic and pneumatic part behaviours in a purely digital analysis and report", explains Eric Noppe, a research scientist at the UTC-Roberval laboratory and head of the UTC Chair of Hydraulics and Mechatronics involved with the SIM-brake Project. In the regional context, it is the company Faiveley Transports based at Amiens alongside the CETIM (technical reference agency for mechanical engineering industries) who are the partners to this project. The work schedule is set out to year 20126, with a budget in excess of 1 Meuros and largely under the management of the relevant industrialists concerned.

When modelling accelerates development

"Nowadays, it takes some 5 years to develop a brake system for a railroad train", asserts Eric Noppe whose ambition it is to cut the time needed by a factor 2 using digital modelling techniques. "Development of these systems usually calls for a long series of iterations between the moment the system is specified technically and integration of the parts to rolling stock and certification", explains Eric Noppe. Modelling moist lead to a truly clear breakthrough in methodology, significantly improving on the maturity of the product testes when it comes into to the final certification phase. Virtual prototypes are made at each stage of product development and this ensures a significant gain in time, avoiding the designers to have to backtrack to the workshop to correct design errors.

Of-the-shelf software with tailor-made parameters

These sorts of tools are largely used in the aeronautics and automobile sectors to guarantee the correct specifications and most efficient component parts/systems possible. This allows industrialists to reduce costs and lead times in development. However, they are not yet in widespread use in the mechanical engineering sectors, such as railroad transportation and agricultural machinery. When it comes to designing brake systems, "functional modelling become very complex indeed", explains Eric Noppe. The modelling process must cover system geometry, friction, fluid (hydraulic and or pneumatic) mechanics and well as all kind of external sources of system disturbance, such as wide variations in ambient temperatures that potentially modify part characteristics. The modelling tools used already exist and can be purchased off-the-shelf but require fine-tuned parameters for the applications envisaged. They are based on theoretical knowledge of the materials and part shapes as well as the industrialists' know-how and technical savvy. The parameters are then adjusted using the results of some basic tests that enable scientists to perfect the model. The research team only needs to await the end of the design period and the start of operational tests, scheduled in 2016, to ensure that the system is operational or whether it needs yet further returns to the certification stages. There is no doubt that the experience acquired will benefit to those industrialists who have expressed a demand for these systems.