UIC B169.1/DT1-1ed.

Anotácia textu normy UIC B169.1/DT1-1ed. :

Summary:

lock / Wheel interaction" is a sector project involving brake block manufacturers, entities in charge of the maintenance of wagons (ECM), railway undertakings (RU), UIC staff, universities, wagon keepers and wheel and brake block manufacturers. Its goal is to define the appropriate conditions for managing brake block / wheel interaction, avoiding safety risks and restrictions in the use of tread-braked wheels, improving the reliability of the system and improving and harmonizing rules to prevent approaches based on singular experience.

The sector project is structured in three major work packages: 

- WP1 "Analysis of the state-of-the-art, calculations and tests specifications"

- WP2 "Calculations, laboratory & field tests"

- WP3 "Summary of the results"

WP1 is articulated in four activities: 

- Activity 1.1 Influence of the operational conditions on wheel design,

- Activity 1.2 Wheel design worst case scenario assessment,

- Activity 1.3 Braking heterogeneity assessment and

- Activity 1.4 Brake block characteristics - impact on energy distribution.

The specific tasks to be managed by the Expert Team in charge of WP1/Activity 1.2 (ET 1.2) were: 

- "Braking worst case scenario study", 

- "High temperature metallurgical bibliographic study and analysis", 

- "Residual stress threshold bibliographic study and technical analysis", and 

- "Definition of specifications for numerical simulations, tests and laboratory analysis". 

The objective is to provide test input data and/or criteria to include UIC Leaflet 510-5 [2] and EN 13979-1 [3] and to provide test specifications for studies proposed to be performed in WP2. Upon completion of the work, the Expert Team in charge of WP1/Activity 1.2 defined and detailed six proposals for work in WP2. 

The present report details the work performed in accordance with "Proposal for numerical investigation of impact from combined thermal and mechanical loads on web fatigue". The JNS Broken Wheels 2019 [4] identified amongst other things that there is a lack of knowledge when it comes to the combined (simultaneous) effect from thermal loads and mechanical loads. Today, these loads are analysed separately in EN 13979-1. In the present report work, the focus is on the fatigue assessment of wheel webs when accounting for the impact from elevated temperatures from tread braking on the fatigue assessment of the mechanical loads stemming from the wheel-rail contact. Analyses with different degrees of complexity are performed. Wheel - rail contact load magnitudes are assumed to be in accordance with EN 13979-1. Braking temperatures are assessed for in-field conditions and severe downhill braking conditions.