Week 2 Bevel Gear Challenge

AIM:
To understand the concept of the grid dependency test and then run the simulation on bevel gear with 4mm, 5mm, and 6mm
element size to evaluate the von-mises stress, equivalent stress, and total deformation on the bevel gear.

OBJECTIVE :
Getting the overall concept of the grid dependency test and how it uses in the Ansys workbench for the simulation process, the
same process needs to be applied on the bevel gear component with different element size such as 4mm, 5mm, and 6mmm but
the facing of the gear should be consistent at 1.75mm. And obtain the result for Von-misses stress, equivalent stress, and total deformation.

THEORY:

Grid dependency Test- A simple concept to understand the "grid dependency test" or "mesh refinement test" in the finite
element analysis that analysis begins with a coarse mesh and it is refined to a finer mesh for each run until the result does not
change significantly. The finer mesh flow will have high accuracy results compare to the default mesh generated.

The main flaw of the finer mesh flow has the elements and node size will increase compared to the coarse mesh size and it we
take a lot of time to evaluate the result. As this test will benefit for an accurate result because of the high-density mesh.

The main concept of this test will be to find optimum mesh size for the evaluation, where it is neither too coarse mesh nor fine
mesh, as it will consume a lot of computing time to generate results.
Because of it, the grid dependency test will be evaluated on the bevel gear to obtain the optimum mesh size.

Bevel Gear- This type of gear where axes of two shaft intersect and the tooth-bearing faces of the gear themselves are conical
shaped. The bevel gear is mostly mounted where the shafts that are 90 degrees to each other but they can be worked at othe
angles as well. The pitch surface of bevel gear is cone.

Fig 1: bevel gear

PROCEDURE:
SETUP

Using the static structural material for the bevel gear as the properties of static structural is mentioned below:

Fig 2: Properties of static structural

The geometry is imported in SpaceClaim and edited with the unwanted extra surface that needs to be cut down for the big gea
with 45mm and to the small gear with 25mm, which unnecessary part and not required for the simulation process.

Fig 3:
Removing unnecessary surface

The geometry is opened in the mechanical module for the simulation process whereas renaming the gears with big gear/solid an
small gear/solid. The material for the bevel gear is given as standard as static structural and the coordinate system as a globa
coordinate system.
On the connection based the contacts to be named on the (Renamed Based on definition) - frictional bevel16t - to bevel24t.

Fig 4: Renamed based on the definition
Contacts Selecting the faces for contact body - 16 Faces and target body 24 faces.

Fig 7: Contact and target setup

Joints
Two revolute joints are provided for the big gear and small gear as connection type (Body-Ground) and type- revolute

Fig 8:
Revolute joint big gear

Fig 9: Revolute joint small gear

As this project is focused on the grid dependency test which evaluates the mesh that changes the resulting output in the bevel gear simulation first the geometry is mesh which 6mm in size.

Fig 10: 6mm mesh

Fig 11: 6mm mesh statistics

For all the other three mesh sizes and for their solution to obtain the accurate results, the face sizing both gear faces are selected with and mesh with 1.75mm size.

Analysis settings
For setting up the simulation for taking out the result the 6 steps are taken with an auto time step on, defined by time and Initia time step 0.1s, minimum time step 0.005s maximum time step 1s.

Fig 12: Analysis settings

Joint Moment

To rotate the big to the opposite side of the small gear joint is given to it with selecting the inner surface of big gear with the type of moment and magnitude as tabular data with 100 Nmm of force at each step.

Fig 13: Joint load moment

Joint Rotation
To rotate the small gear joint rotation is given with selecting inner surface and type of rotation with the angle of 20 degrees at each step.

Fig 14: Joint load rotation

As the small gear is rotating about the same axis rotation so to rotate the opposite side, the coordinate system has been change to change the angle of rotation to the RZ axis.

Fig 15:Changing the coordinate system

For evaluating the result for the grid dependency test for 6mm, 5mm, and 4mm mesh size the output is obtained for Equivalent Von mises stress, Equivalent elastic strain, and Total deformation.

RESULT
Case 1: For 6mm size and face sizing 1.75mm size

Fig 16: Equivalent stress

Fig 17: Equivalent strain

Fig 18:Total deformation

Now for the other mesh size result we have used the parametric options in Ansys workbench

We have just vary the mesh size as input from user as 6mm,5mm and 4mm. These are the parameteric inputs from user.

For output we have specified mainly von mises stress and total deformation with minimum, maximum and average values as given in above picture

The project schematic page shows all this details in the parameter tab at the static structural tree.

Comparision of results :

Conclusion:

On comparing the total deformation of three cases there a considerable difference between case1 and case2,case 2 and case 3 are
almost similar.
On comparing the equivalent stress there a considerable difference between case1 and case2,case 2 and case 3 are almost similar.
By comparing equivalent elastic strain there a considerable difference between case1 and case2,case 2 and case 3 are almost
similar.
Grid dependency test, where, analysis begins with a coarse mesh and it is refined to finer mesh for each run until the results do no
change significantly and depend of the grid size anymore.
As the grid or mesh size approaches zero, the approximate solution is almost equal to the actual solution.

kindly download the ansys files from below link :

https://drive.google.com/file/d/1Pm_NHTbZEFn-QH6GbSey9gzIeGjn6CG6/view?usp=sharing