Week 1 Spur Gear Challenge
objective: To perform the analyses of the pair of spear gear by assigning to them different material properties and studying the difference in certain behaviour of the set.
procedure:
setting up the simulation: To set up the simulation, first we need to import all the required material cards such as cast iron,cast steel, and cast bronze.
the above material can be found in the granta material library
cast iron
cast steel
cast bronze
importing geometry:
next we import the geometry which the creo CAD file of the 2 gears which has been provided
material definition:
The material cast iron is assigned to the gears for the first case
then we will open ansys mechanical to set up the rest of the simulation.
to set up the contact we go to connection-->contacts and open the contact card.
we will create the contact by selecting the faces on both the gears as shown. just the addendum and dedendum is selected which is one continuous surface on both side of each of each gear tooth. So from both gears 26 faces are selected respectively
type = frictional
formulation = Augmented lagrange
interface treatment = Adjust to touch
Next we define the joint for both gears
In this way both the joint are selected as body-ground and revolute type.
Next a mesh is generated of 0.5mm as shown below.
creation of joint-loads: Next we assign the motion to the individual gears. This can be done by giving rotation or a moment .
for the first gear we provide rotation by increment of 30 degree as shown below by inputting data into the table the motion is given in the form of 10 increments.
for second gears, we inputting a moment in the opposite direction of rotation to the first gear as shown below. The torque provided is of the order of 10000 N-MM which is equal to 10 N-M which is constant from the begining till the end .
setting up the analysis setting: Next the analysis setting a selected as shown below inputting the values of number of step initial time-step mac/min time step.
output parameter: The following parameter are selected for output from the simulation
Running the simulation:
Next we run the simulation the simulation takes a very long time to run as we can see from the runtime below.
post processing: The simulation is run for all the 3 material by changing material assignment and re-running it
1.cast iron
2.cast steel
3.cast bronze
equivalent stress:
1.cast iron
A peak stress of 580.58MPA is obtained is obtained at the middle of the height of the gears tooth as shown below
cast steel
A peak stress of 540.87 is obtained for cast steel
cast bronze
A peak von-mises stress value of 526.12 mpa is obtained for cast bronze.
stress intensity
1. cast iron
The intensity is equal to the resultant of compressive and tensile forces at a particular point
as we can see the peak stress intensity of 655.77mpa is obtained for cast iron gears
2. cast steel:
As we can see the peak stress intensity of 609.96mpa is obtained for cast steel gears
3. cast bronze
As we can see the peak stress intensity of 586.21mpa is obtained for cast bronze gears.
Total deformation:
The total deformation is calculated as follow. Although this may not be accurate as we are dealing with moving parts.
1. cast iron
To get accurate deformation reading we can request for equivalent strain outputting as shown below. As we can see a maximum strain of 0.0058 is obtained which is equal to 0.58%
2. cast steel
A peak equivalent strain value of 0.00476 which is equivalent to 0.476% is obtained
3. cast bronze
A peak equivalent elastic strain value of 0.01154 which is equal to 1.15% is obtained which is significantly higher than cast steel and cast iron options
this is due to the lower yield strength of bronze as compared to iron and steel.
conclusion:
Based on the result obtained above we find out that cast steel offers the best compromise as it has shows the lowest strain rate and comparably low stress when compared to cast iron. hence the proper material to be chosen based on the above simulation is cast steel.