Thermo-Mechanical Analysis of Friction Brake Block for Freight Train A.A-Djibouti Main Line
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Date
2015-02
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Addis Ababa University
Abstract
The main purpose of this study is to analyze the thermo-mechanical behavior of the contact between the brake block and wheel during the braking time and at two different contact angle brake block. The simulation strategy is based on the commercially available FEM software packages, ANSYS and CATIA modeling. The model is simulated using a 3D brake block in order to observe the surface temperature distributions profile for applied braking condition using brake block materials. The temperature rise and the loads are formulated analytically. The transient thermal and transient structural analysis is used to generate the output of the research and the output gives appropriate value for two different angle of contact different value of temperature rise, deformation and stress induced on the brake block. Therefore, the thermal analysis of a block-braked material on a freight train of the national railway operator Ethiopian Railways using analytical and numerical modeling of thermal effects during braking and in one wheel side have two brake blocks the highest temperature are after emergency braking was 459.1℃ contact surface area 30o and 245.2℃ at contact surface area of 45o, which occurred at 9.48second and service braking, was 412.86℃ contact surface area 30o and 222.45℃ at contact surface area of 45o, which occurred at 12.1second. In one wheel side have one brake block the highest temperature after emergency braking was 899.49℃ contact surface area 30o and 471.68℃ at contact surface area of 45o, which occurred at 9.48second and service braking, was 793.66℃ contact surface area 30o and 423.44℃ at contact surface area of 45o, which occurred at 12.1second.
The maximum deformed and strain to a part of the brake block (shoe) result from cumulative effect of the thermal and pressure load applied on one wheel side have two brake blocks during emergency brake the deformation are 0.0000339m for θ=300 and 0.0000204m for θ=450. During service brake the deformation are 0.0000283m for θ=300 and 0.0000188m for θ=450. In one wheel side have one brake block the maximum deformed and strain to a part of the brake block (shoe) during emergency brake the deformation are 0.0000690m for θ=30 and 0.0000439m for θ=45 and the maximum strain for θ=30o is 0.01024 and for θ=45o is 0.00673. During service brake the deformation are 0.0000568m for θ=300 and 0.0000412m for θ=450 and the maximum strain for θ=30o is 0.00842m and for θ=45o is 0.0060m.In one wheel side have two brake blocks the maximum equivalent (Von mises) stress induced on the brake block during emergency brake is about 5.3568*108N/m2 (535.68Mpa)for θ=300 and 3.4325*108N/m2 (343.25Mpa) for θ=450 respectively and during service brake is about 4.5954*108N/m2 (459.54Mpa)for θ=300 and 3.0735*108N/m2 (307.35Mpa)for θ=450. In one wheel side have one brake block the maximum equivalent (Von mises) stress induced on the brake block during emergency brake is about 1.1264*109N/m2 (1126.4Mpa) for θ=300 and 7.402*108N/m2 (740.2Mpa)for θ=450 respectively and during service brake is about 9.2645*108N/m2(926.45Mpa)for θ=30oand 6.6075*108 (660.75Mpa)for θ=45o.
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Keywords
rail way, brake block, temperature rise