Week 2 Railwheel and Track

objective: To perform the simulation of motion of a rail wheel on a track and obtain the desired output.

procedure:

setting up the simulation

To set up the simulation, first we need to import the required material card of structural steel. This material can be found in the general material liberary.

Importing geometry which the CAD file of the rail, wheel and shaft which has been provided the parts are rennamed as running rail, wheel and shaft respectively for ease of understanding.

material definition:

The material structural steel is assigned to all components the we will open Ansys mechanical to set up the rest of the simulation.

To set up the contact we go to connection-->contact and open the contact card

we will invert the contact and target bodies and rename the contact as definition based we will create 2 contact

between rail and wheel

between shaft and wheel

for the contact between rail and wheel select contact type as frictional,

coefficient of friction =0.3

for the contact between wheel and shaft select contact type as frictionless as shown above thus contact definition is complete

Next we define the joint for the simulation

first we define the body-to-ground translation joint for the shaft. this is to enable it to move straight along the direction of the motion of the wheel. select the coordinate system geometry so that the direction of motion.

align with the x-axis as shown above.

Next we define a body-to-ground planar joint to keep the wheel locked is lateral motion and enabling it to rotate. about it own axis as the shaft moves forward. for the scope we select the back face of the wheel as shown above.

Finally we define a body-to-ground fixed type joint to constrain the rail to the ground to prevent its motion during the simulation. for the scope we select we select the lower face of the rail as shown above

Next a general mesh is generated of 30mm with face sizing applied of 10mm on the two areas in contact.

The face sizing is applied since that is the surface in contact and which will experience loads hence we want accurate result hence we apply a finer mesh in these regions. the selected areas for face sizing.

creation of load condition: Next we assign the translation motion to the wheel shaft. This is done by providing department in the form of 5 increment each of 100mm each.

we verify that the direction of translational is in the one which we want along the length of the rail.

for the second load, we provide a bearing load on the inner case of the wheel to simulate the mass of the carriage which will be carried by wheel.

A load of 10,000N is applied in the downword direction ia applied on the wheel as shown by the red highlighted area above.

setting up analysis setting: Next the analysis setting are selected as shown below inputting the values of number of steps, initial step, maximum/minimum timestep we select as total of 5 steps with the above given values for initial ,max and min timestep.

running the simulation:

The simulation runs in about 20min as shown above with a successful result

during the run we can check whether the simulation is converging by checking the force convergence graph

we will evaluate the below result based on two loading condition

bearing load 100000 N

bearing load 500000 N

stress

case 1:

A break stress of arounnd 768 Mpa is obtained on the wheel towards the end of the run

case 2:

for the second load stress of 1363.6 Mpa is generated on the wheel which is a 77% increase in the stress from the previous load case.

strain

case 1:

A peak strain of 0.6% is obtained on the wheel towards the end of the run as we can see above

case 2:

A peak strain of 0.8% is obtained on the wheel which is a 33% increase from the previous load case

total deformation:

user defined result:

Now we will see the result of our user defined option As we can see the result is exactly similar to total deformation hence we have successfully executed a user defined output command.

conclusion:

hence the simulation of motion of wheel on a rail has been simulated and we have compared the result of different loading cases as well as generated the desired output from a user defined load case.