Railway Contact Analysis

ABSTRACT

Wheel-rail contact analysis is one of the most standout problems in the modeling and analysis of railway vehicles. The wheel-rail interaction is an exceptional part of rail-vehicle progress as it accounts for the capacity of freight wagon and is being considered the most critical parameter for the freight traffic wagons on the railway tracks. In this thesis, the static response of the wheel on a rail is analyzed by modelling and analyzing the geometries of standard section of Rail and wheel through the softwares Creo parametric 2.0 and Ansys 15.0 for calculating the stresses between the Rail-wheel contact region. An analytical approach for calculating the tangent modulus is been drafted during the selection of material and its properties

The development is for the most part is stable aside except the zones where clayey soil or other sorts of shrinkable soils are found. The majority of the track is straight with the exception of 16% of the track on BG and MG and 20% of the track on NG, which is on curves. The most extreme level of curve allowed is 10° on the Broad gauge, 16° on the meter gage, and 40° on the Narrow gauge. The ballast utilized is broken stone counterbalance, however in a few ranges, sand and coal ash have additionally been utilized. Around a 20 cm to 30 cm (8" to 12") cushion of ballast is typically given underneath the sleepers to transfer the load equitably and to give the essential flexibility to the track. The diverse materials used to build sleepers are wood (31%), cast iron (42%), and steel (27%). Experience has demonstrated that cast iron sleepers are not capable for high-density routes. Solid concrete sleepers have been created by Indian Railways and are proposed to be continuously laid on gathering on group A and B routes which are high speed lines of 160 km/h and 130 km/h on broad gauge routes.

Sleepers are laid to different sleeper densities differing from (M + 7) to (M + 4) or 1540 for each km to 1310 for each km relying on the weight and volume of movement. Here M remains for length of rail in meters.

Normally its value is 5 or more than 5.

Using this expression the value tangent modulus is 34 000 Mpa. Tangent modulus is used to find the value of slope in stress-strain curve beyond the yielding point. The term is little bit confusing as it doesn’t give indication about stiffness, and elastic behaviour but estimates the hardening effect.

For structural steel the values are

Et = 20000 Mpa, E = 2 x 105 Mpa σys = 250 Mpa

Inserting these values in the formula of tangent modulus, we get the following results 2 x 105 x 250 20000 = 250 + 0.002 n x 2 x105 (σ/σys)n-1

n(σ/σys)n-1 = 5.625

if , ( ( σ/σys)n-1 )structural steel = ( ( σ/σys)n-1 )cast steel Grade 880 then,

For Cast steel Grade 880 we have the following values

Et = ? E = 2.1 x 105