Spur Gear Challenge

TITLE: understanding the effect of static structural analysis on a Spur Gear.

SUMMARY: In this project,we are going to perform a static structural analysis on a Spur Gear with under three different materials assigned.Here we will be keeping the Boundary Conditions constant and will carryout the results for differnt materials accordingly.

Introduction: Spur gears are the most common type of gears. They have straight teeth, and are mounted on parallel shafts. Sometimes, many spur gears are used at once to create very large gear reductions.They are the simplest and widely used in power transmission. In recent years it is required to operate machines at varying load and speed. Gear teeth normally fail when load is increased above certain limit. Therefore it is required to explore alternate materials for gear manufacturing. Composite materials provide adequate strength with weight reduction and they have emerged as a better alternative for replacing metallic gears.

So far the Load is concerned,every gear acts differently when it is under different loading conditions. Ansys Workbench allows us to predict the exact generated parameters such as Equivalent Stress,Deformation,Stress Intensity etc. Here we are provided with a spur gear geometry as shown below,it is visible that both are in contact with each other

Spur Gear Model

In order to perform simulation for above model,we have assigned three cases for different materials.The materials we will be using are nothing but the Cast Iron,Cast Steel and Cast Bronze. At the end of this project we will be able to see how under loading conditions,different materials on gear acts differently. We began the simulation by providing the proper contact & Targeted body consideration.We assigned the materials starting with cast iron meanwhile we meshed the model in order to get all those meaningfull results. The Meshed model image & mesh metric Graph can be seen below.

After applying mesh,our model is ready to procced for application of various boundary conditions such as inserting joint connections,and providing necesssary conditions for the sucessfull carryon of simulation including moment,rotational velocity under steps of time,each assigned under the different times.Later we provided the parameters for which we are intrested to obtain. We will be focusing to 1st case where we have assigned cast iron.Here we obtained the Force Convergence graph for initial time of first 30 points.

CASE 01.

For CAST IRON,

the Force Convergence & SubStep Convergence can be seen above

Then, we have assigned the rotaional velocity for about 180 degree in 6 simple steps followed by the Initial Moment of -10mm (here -ve indicates revolving in opposite direction).

Now,we obtain the Equivalent Stress (Von-Mises),Total Deformation, Stress Intensity.A maximum of 460.87 MPa of stress can be seen generated while a minimum of 4.9057e-5 MPa

https://www.youtube.com/watch?v=7i4oBZLNDPk&authuser=0

Similarly, we have Total Deformation for Spur Gear.Here a Maximum Deformation of 30mm can be seen & a minimum of 18.5mm Respectively.

https://www.youtube.com/watch?v=8ulNBr_HGZY&authuser=0

Stress Intensity is one of the most fundamental and useful parameters in all of fracture mechanics. However the stress intensity factor describes the stress state at a crack tip, is related to the rate of crack growth, and is used to establish failure criteria due to fracture.The stress intensity factor predicts stress intensity near the tip of a crack caused by a remote load or residual stresses.

Here, we have obtained a maximum of 520.17 Mpa & minimum of 5.52e-5 Mpa of Stress intensity.

https://www.youtube.com/watch?v=ZLTmTk-FvU8&authuser=0

Observing upon the intensity of stress,we can predict where exactly we have a fracture point.

Meanwhile, Other Parmeters such as "Pressure" & Status regarding contact,touch etc.can be seen below,

Pressure

Status

CASE 02

For case 2,we have given cast steel as a working material.Following every procedures we have conduct above we may obtain similar parameters for different materials.

Mesh Metric & Meshed Model,

Equivalent Stress:

https://www.youtube.com/watch?v=LRyIDPX86m0&authuser=0

Total Deformation:

https://www.youtube.com/watch?v=V3_RfYmKtuE&authuser=0

Stress Intensity:

https://www.youtube.com/watch?v=htFl-UQih9w&authuser=0

• CASE 03

Ultimately,we are assigned with Cast Bronze as a working material,similar results are found below

Equivalent Stress:

https://www.youtube.com/watch?v=7PXYcWhG20s&authuser=0

Total Deformation:

Stress Intensity:

here, fracture point can be seen on the extreme right of tip of tooth

The comparision chart below shows which material works better.

• CONCLUSION: It can be observed that cast steel is undergoing very small amount of stress generated. However still common amount of deformation for cast iron & cast steel (i.e 3mm) Hence Cast steel would be best for manufacturing of Spur gear.