COMPOSITION BRAKE-BLOCKS. THE DETERMINATION OF CHEMICAL AND PHYSICAL PROPERTIES OF COMPOSITION BRAKE-BLOCKS AND THEIR EFFECT ON THERMAL CRACKING OF TYRES
The determination of the chemical and physical properties of various composition brake blocks, the measurement of maximum surface temperatures on tyres and the possible damage to tyres caused by various composition brake blocks are dealt with in the report. Investigations which have been made enable the following conclusions to be drawn: Improvement of the braking performance on wet rails requires a content of hard materials of not less than 5%. The material selected shall be harder than the tyre steel (based on Moh's hardness scale). There is no obvious correlation between chemical composition and modulus of elasticity. Brake blocks with a high modulus of elasticity produce high local temperatures and thermal damage. The modulus of elasticity should not therefore exceed 100 daN/mm to the 2nd power. Maximum surface temperatures (hot spots) are influenced principally by peripheral speed at the beginning of braking. The value of axle load also has a pronounced effect, whereas variation in brake block load has in general only a minor effect on the values of the surface temperature. Maximum surface temperatures should not exceed 600 degrees C in order to avoid thermal cracking.
- Restrictions on the use of this document are contained in the explanatory material.
International Union of RailwaysOffice of Research and Experiments
- Publication Date: 1971-4
- Features: Appendices; Figures; Tables;
- Pagination: 37 p.
- TRT Terms: Brake shoes; Brakes; Braking; Braking performance; Composite materials; Elasticity (Mechanics); Measuring instruments; Thermal stresses; Vehicle tests
- Old TRIS Terms: Brake tests; Hot spots; Question b64
- Subject Areas: Railroads; Vehicles and Equipment;
- Accession Number: 00052940
- Record Type: Publication
- Source Agency: International Union of Railways
- Report/Paper Numbers: B64/RP 9/E
- Files: TRIS
- Created Date: Sep 16 1976 12:00AM