UIC brake pad certification

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1 UIC brake pad certification Railway Brake and Friction Conference Derby, 2017 Prof. Dr.-Ing. Matthias Niessner Munich University of Applied Sciences Railway Research Group Railway brake systems Why is a consistent friction behaviour important for safe train operation? Trains may not overtake or step aside. Collisions can cause significant damage. The railway system is based on fixed presignalling distances and requires predictable and consistent stopping distances. Brake control operates with predefined brake steps. Changes in frictional behaviour result in longer or shorter stopping distance. For safe train operation it is essential to use friction material with predictable and stable behaviour simulate and evaluate possible critical events UIC brake pad certification Matthias Niessner hm.edu/rail 2

UIC-leaflet 541-3 UK Standards GM/RT2041 Coaches, GM/RT2042 Motor Units, GM/RT2043 Freight, GM/RT2046 High speed 1) Standards based on performance curves for train tests 2) Typically upper and lower

2 UIC-leaflet UK Standards GM/RT2041 Coaches, GM/RT2042 Motor Units, GM/RT2043 Freight, GM/RT2046 High speed 1) Standards based on performance curves for train tests 2) Typically upper and lower curves are given ( min. and max. adhesion) Standards were superseded in 2016 by new GMRT2045:2016 Compatibility Requirements for Braking Systems of Rail Vehicles RSSB GM/RE2041 Trailer Coaches from 2000 Now included: Dynamometer testing of brake pads with reference to UIC 541-3:2010 (as long as EN15328 Brake pads is not available) Brake pads with friction characteristics outside UIC tolerance can be used, but operational restrictions during winter season need to be defined by the operators if necessary. UIC brake pad certification Matthias Niessner hm.edu/rail 3 UIC-leaflet Background The leaflet describes the technical requirements a friction material has to fulfil to obtain a UIC product certification. Historically the UIC leaflet was introduced in 1977 for disc brake systems for passenger coaches 200 km/h. Certified brake pads can make the vehicle certification process simpler (and faster) show a minimum required level of reliability and safety should in general be interchangeable if tested with same programme Picture Flieger UIC brake pad certification Matthias Niessner hm.edu/rail 4

3 Previous7 th editionof the UIC leaflet541-3 Sample test programme in 7 th edition BEDDING STOPPING Extract from UIC CONTINUOUS UIC brake pad certification Matthias Niessner hm.edu/rail 5 Previous7 th editionof the UIC leaflet541-3 Basic evaluation concept in the 7 th edition of the leaflet Stop brake applications:instantaneous and mean µ-values (over stopping distance s) have to be within fixed given limits (dry brake applications) Instantaneous friction µ a =µ(t) for 2,3, and 6 Mean friction µ m for 2,3, and 6 Brake pads with reliable and stable friction behaviour, but outside of fixed tolerance bands will not achieve certification. UIC brake pad certification Matthias Niessner hm.edu/rail 6

Previous7 th editionof the UIC leaflet541-3 Pros and cons of the 7 th edition from 2010 Real brake pads hardly (never )

Test programmes are inconsistent with EN 14535-3 v brake discs and performance of friction pair Well-known standard with

No flexibility in case of single brake events outside tolerance.

Unrealistic brake scenarios and requirements under wet conditions. UIC brake pad certification Matthias Niessner hm.

4 Previous7 th editionof the UIC leaflet541-3 Pros and cons of the 7 th edition from 2010 Real brake pads hardly (never ) meet all requirements of 7 th edition. Test programmes are inconsistent with EN v brake discs and performance of friction pair Well-known standard with known limitations Works quite well with organic brake pads for passenger coaches. No flexibility in case of single brake events outside tolerance. Different test programmes for sinter and organic brake vpads for the same application. Unrealistic brake scenarios and requirements under wet conditions. UIC brake pad certification Matthias Niessner hm.edu/rail 7 New demands for friction material Picture Siemens heavy large brake discs Gravita, Picture VOITH high-speed up to 400 kph large variation of braked mass due to blended braking (R+ED+MTB/ECB) large variation of braked mass for container carrier (2-11 t per disc) Picture Astrarail UIC brake pad certification Matthias Niessner hm.edu/rail 8

Split of certification procedure according to vehicle classes New vehicles Passenger Coaches Picture Siemens New test programmesfor freight, multiple units, and locomotives New and more consistent

5 Split of certification procedure according to vehicle classes New vehicles Passenger Coaches Picture Siemens New test programmesfor freight, multiple units, and locomotives New and more consistent certification criteria All test programmes for sintered and organic brake pads Old rules still apply for passenger coaches and highspeed trains with 4 t braked mass Allows a new certification of existing and proven friction material for coaches Certified friction material can still be used for existing, but not for new built vehicles UIC brake pad certification Matthias Niessner hm.edu/rail 9 Basic conclusions of the working group for frictional requirements New test programmes need to be consistent with standards like EN Consider friction materials speed-dependent behaviour Safe and consistent, but more flexible! Baseline Concept (fingerprint) Nominal µ-behaviourdescribed by an individual, speed-dependent Nominal Line derived from the pad behaviour during the test Prioritisation of brake applications based on their impact on safety and frequency of occurrence in real operation. UIC brake pad certification Matthias Niessner hm.edu/rail 10

6 Consistency with EN Performance of brake discs and friction pair A1 increased to t from 10 t, deceleration lowered to 0.9 from 1.2 m/s² C3 added with 12 t and 200 km/h (class with highest braking power of 800 kw) D1 decreased to 6.5 t from 8.5 t D2 added with 10.5 t Class Max. energy in MJ Max. power in kw Max. speed in km/h Max. braked mass in t Max. calc. deceleration rate in m/s² Max. FB in kn(w/o parking) Application A1 6, ,25 0,9 46 Freight cars (AMD) B1 7, ,2 44 B2 9, ,2 55 C1 12, ,2 44 C2 15, ,2 55 C3 18, ,2 54 MU, Loco (WMD) MU, Loco (WMD) D1 15, ,5 0,8 37 MU (AMD) D2 25, ,5 0,8 55 MU (WMD) E1 27, ,8 49 High-speed (WMD) F1 23, ,8 25 F2 28, ,8 37 High-speed (AMD) F3 33, ,8 43 High-speed (WMD) G ,8 37 High-speed (AMD) UIC brake pad certification Matthias Niessner hm.edu/rail 11 Prioritisation of Stop brake applications Priority levels from 1 to 4 to consider the safety relevance Brake applications with highest clamp force under normal conditions simulate EB braking Prio1 Priority level Type of brake application Dry with the highest clamp force for each mass under normal conditions Wet or hot brake applications with highest clamp force, independent from braked mass Highest clamp force used for cleaning, drying, regenerating, or after continuous brake applications, independent from braked mass All other brake applications except brake applications with 4 Priority 0 0* Continuous brake applications, bedding, static friction UIC brake pad certification Matthias Niessner hm.edu/rail 12

Evaluation with Nominal Line and Prio-dependent Tolerance Bands µ m

defined number of admissible violations of TB 1 2.

and 4 Limits for Nominal Line Tolerance bands for single brake

±30% UIC brake pad certification Matthias Niessner hm.

7 Evaluation with Nominal Line and Prio-dependent Tolerance Bands µ m 0,47 0,28 speed v v min v max Certification (yes/no) is based on 1. defined number of admissible violations of TB 1 2. no tolerance against TB 2 violations Prio1 Nominal Line (NL) Prio2,3 and 4 Limits for Nominal Line Tolerance bands for single brake applications Prio TB 1 TB 2 1 ±10% ±15% 2 ±15% ±20% 3 ±20% ±25% 4 ±25% ±30% UIC brake pad certification Matthias Niessner hm.edu/rail 13 Sample dataset for A1 (stop brake applications) UIC brake pad certification Matthias Niessner hm.edu/rail 14

Overview of µ m -values as function of speed, including Nominal Line Nominal Line from linear regressionof Prio1 stops Limits for the Nominal Line (0.28 to 0.

8 Overview of µ m -values as function of speed, including Nominal Line Nominal Line from linear regressionof Prio1 stops Limits for the Nominal Line (0.28 to 0.47) Own picture UIC brake pad certification Matthias Niessner hm.edu/rail 15 Prio1 brake applications including TB1 (±10%) and TB2 (±15%) Nominal Line from linear regressionof Prio1 stops Prio1brake applications only TB 1(±10%) TB 2(±15%) Priority 1 12 %of all µ m -values of Priority 1 are acceptable in TB 2, but only 6 % of all µ m -values of Priority 1 are acceptable in the lower part of TB 2. All other µ m -values must be in the space o TB 1. UIC brake pad certification Matthias Niessner hm.edu/rail 16

Prio 2, 3, and 4 brake applications including tolerance bands Priority 2-4 10 %of the total number of µ m -values of Priority 2, 3 and 4 are acceptable in TB 2, but only 5 %of in the lower part of TB

edu/rail 17 Validity of certificate 10 years (unless problems are identified in service) Application for renewal at least 6 month before expiry date renewal based on proof by dynamometer test only

9 Prio 2, 3, and 4 brake applications including tolerance bands Priority %of the total number of µ m -values of Priority 2, 3 and 4 are acceptable in TB 2, but only 5 %of in the lower part of TB 2. All other µ m -values must be in the space of TB 1. UIC brake pad certification Matthias Niessner hm.edu/rail 17 Validity of certificate 10 years (unless problems are identified in service) Application for renewal at least 6 month before expiry date renewal based on proof by dynamometer test only Certificate will loose its validity in case of major changes in the manufacturing method or raw materials major changes in the fixing of sintered friction elements changes in the friction area exceeding ±20% Approved pads are listed on the UIC internet pages (free download) UIC brake pad certification Matthias Niessner hm.edu/rail 18

UIC evaluation tool Software tool from Munich University of Applied Sciences UIC brake pad

edu/rail 19 Rules for interchangeability Brake pads are interchangeable if 1) Both pads are tested

reference) is already in use on trains and has been used to evaluate the brake performance of the

critical train speed are defined considering

difference must not exceed +10% and -5% of the reference value) 4) For any other speeds than v crit

10 UIC evaluation tool Software tool from Munich University of Applied Sciences UIC brake pad certification Matthias Niessner hm.edu/rail 19 Rules for interchangeability Brake pads are interchangeable if 1) Both pads are tested with the same UIC test programme preferably on the same dynamometer 2) One of the two pads (the reference) is already in use on trains and has been used to evaluate the brake performance of the train during certification 3) The possible difference of the µ m -values under dry conditions at critical train speed are defined considering the specific train application (e.g. difference must not exceed +10% and -5% of the reference value) 4) For any other speeds than v crit the µ m -values must be greater or equal to the µ m -values evaluated at v crit Remark TSI recommends/requires vehicle tests to define interchangeable brake pads. Due to good experience with coaches UIC stays with interchangeability assessment based on dynamometer tests. UIC brake pad certification Matthias Niessner hm.edu/rail 20

11 Pros and cons of the new 8 th edition from 2017 New performance classes consistent with EN One test programme for each class independent from organic or sintered friction material Nominal Line gives basic fingerprint of the pads friction characteristic Old rules are still used for brake pads for passenger coaches Introduction of Prio-levels 1 to 4 allow larger deviations for noncritical (non-eb) brake applications Evaluation software available UIC brake pad certification Matthias Niessner hm.edu/rail 21 Contact Prof. Dr.-Ing. Matthias Niessner Munich University of Applied Sciences Department of Applied Sciences and Mechatronics Railway Research Group Lothstr. 34, D München, Germany matthias.niessner@hm.edu UIC brake pad certification Matthias Niessner hm.edu/rail 22

12 Curriculum Vitae Prof. Dr.-Ing. Matthias Niessner University of Applied Sciences Frankfurt Mechanical engineering Darmstadt University of Technology Mechanics Doctoral thesis in mechanics of materials and fatigue Keystone Railway Technology, Neitersen Design of crash systems for railway vehicles Knorr-Bremse Systeme für Schienenfahrzeuge, München Design of brakediscsand pads Munich University of Applied Sciences Professor Research areasrailwaybrakesystems, improvementof wheel-railcontact, vehicle dynamics, and additive manufacturing in railway systems Member of UIC working group B126/541-3 certification of brake pads UIC brake pad certification Matthias Niessner hm.edu/rail 23

Friction Material. Freight Cars High-Speed Trains Light Rail Vehicles Locomotives Metros Passenger Coaches Regional and Commuter Trains

Friction Material. Freight Cars High-Speed Trains Light Rail Vehicles Locomotives Metros Passenger Coaches Regional and Commuter Trains Friction Material Applications Freight Cars High-Speed Trains Light Rail Vehicles Locomotives Metros Passenger Coaches Regional and Commuter Trains 2 KNORR-BREMSE A FULL LINER IN FRICTION MATERIAL Our