GRID DEPENDENCY TEST ON BEVEL GEAR ASSEMBLY

AIM:

To perform a grip dependency test on a bevel gear assembly for mesh sizes 6, 5, ans 4mm.

GRIP DEPENDENCY TEST:

• Grid dependency test ia a method used in FEA to get the optimum results by reducing mesh density in a given component.
• Mesh refinement, mesh convergence are the other names used to define Grid dependency test.

PURPOSE OF GRID DEPENDENCY TEST:

• The simulation softwares does not provide us the accurate mesh size for our model to get the optimum results, their work is to provide the results by conducting simulation based on the mesh size entered by us. Thus our job is to enter the correct mesh size to begin a simulation that results in optimum value. As a human we don\'t know the correct mesh size to get the optimum results. Hence we are undergoing grid dependency test.
• Here in grid dependency test we start the simulation with coarse mesh or a greater mesh element size and then we reduce the mesh element size step by step till we get the optimum result after which there won\'t be any changes in the optimum results even though we further refine the mesh.

PROCEDURE FOR GRID DEPENDENCY TEST:

MESH ELEMENT SIZE: 6mm

• Select the material for bevel gear as structural steel under the Engineering data menu.

MATERIAL PROPERTIES OF STRUCTURAL STEEL

• Import the bevel gear.stp file and then edit the model using the option Edit geometry using spaceclaim.

• Then update the model and then edit the model using the right click.
• In the Mechanical solver under Geometry sub menu rename the components as small gear and big gear for reference.
• Under Contacts sub menu select the faces of both contact and target bevel gears which intersect with each other.
• Under Contacts sub menu create joints option separately for each bevel gear to specify their connection type as body-ground.
• Mesh the model by assigning the elemant size as 6mm and then element size of connecting faces as 1.75mm

• Under static analysis in analysis setting sub menu setup the controls as shown in the image below

• Under static analysis menu create two joint sub menu for each bevel gear for specifying their rotation degrees in anticlockwise direction and moment values in clockwise direction.
• Insert the total deformation, von mises stress solution and elastic strain to analyse the solution of bevel gear. Then press f5 to solve.

TOTAL DEFORMATION

VON-MISES STRESS

ELASTIC STRAIN

MESH ELEMENT SIZE: 5mm

• Once the Analysis setup has been done then the structural analysis for different mesh element size can be done simply changing the mesh size under mesh menu

TOTAL DEFORMATION

VON-MISES STRESS

ELASTIC STRAIN

MESH ELEMENT SIZE: 4mm

TOTAL DEFORMATION

VON-MISES STRESS

ELASTIC STRAIN

COMPARISON OF THE ABOVE RESULTS:

• From the table above, the total deformation value is same for the analysis done using different mesh length i.e., 47.873mm
• The equivalent stress value changes as the mesh length value changes. Here the equivalent stress value increases as we change the mesh element size from 6mm to 5mm and againg it decreases as we change the mesh length from 5mm to 4mm which is an indication that the value is moving towards convergence.
• The elastic strain value also changes as the mesh length changes. Here the elastic strain value increases as we change the mesh element size from 6mm to 5mm and againg it decreases as we change the mesh length from 5mm to 4mm which is an indication that the value is moving towards convergence.

CONCLUSION:

Thus grid dependency test for the Bevel gear simulation for mesh sizes of 6,5 and 4 mm has been conducted successfully and the results are examined.