Challenge

Week 2 Bevel Gear Challenge

Bevel Gear Challenge

Problem statements:

  1. To explain the grid dependency test and its uses.
  2. To perform a grid dependency test for the Bevel gear simulation for mesh sizes of 5, 4 and 2 mm and solve for Von-Mises stress, Equivalent elastic strain, and Total Deformation using the previously mentioned mesh sizes.

Tools used:

ANSYS Workbench 2020 R2

Boundary conditions (Same for all 3 analyses except mesh size):

Part type = Bevel Gears mated at a right angle

Material = Structural Steel

Rotation = 120 degrees

Moment load = 100 Nmm

Material properties

Sl. No. Properties Units Structural Steel
1 Density kg/m3 7800
2 Young's Modulus MPa 200000
3 Tensile Yield Strength MPa 350
4 Tensile Ultimate Strength MPa 420
5 Shear Modulus MPa 79300
6 Poissons Ratio N/A 0.25

Case 1: 6mm mesh size 

  • Setup: A new Static Structural study was created in ANSYS Workbench.
  • Boundary conditions: Structural steel was applied as the material.
  • Frictional contact is established between the small and the large gear.
  • The gears are secured using revolute joints.
  • Mesh: A mesh size of 6 mm is chosen for all bodies and then a finer mesh of 1.75 mm is chosen for certain surfaces where refinement is required using face sizing.
  • Loads: A moment of 100 Nmm was applied and an angular displacement of 120mm in 6 steps was defined to replicate the rotation of the gears.
  • Results: The mesh is generated and Stress, Strain, and Deformation are chosen as the solutions to be evaluated. The results are tabulated in the results section of the report. 

Figure 1: Total Deformation with 6 mm mesh size

Figure 2: Total Deformation plot with 6 mm mesh size

  Time
[s]
Minimum [mm] Maximum [mm] Average [mm]
1 0.2 0.87249 1.8939 1.4263
2 0.4 1.7439 3.7856 2.8554
3 0.7 3.0467 6.6136 5.0044
4 1 4.3412 9.4236 7.1073
5 1.2 5.1978 11.283 8.506
6 1.4 6.048 13.129 9.91
7 1.7 7.3093 15.866 12.012
8 2 8.5505 18.561 14.065
9 2.2 9.3652 20.329 15.414
10 2.4 10.168 22.073 16.762
11 2.7 11.35 24.637 18.765
12 3 12.5 27.134 20.735
13 3.2 13.248 28.758 22.013
14 3.4 13.98 30.346 23.27
15 3.5 14.339 31.127 23.9
16 3.6 14.695 31.898 24.522
17 3.75 15.219 33.036 25.449
18 3.875 15.648 33.968 26.218
19 4 16.07 34.883 26.982
20 4.2 16.728 36.312 28.156
21 4.4 17.366 37.698 29.311
22 4.6 17.983 39.037 30.446
23 4.8 18.579 40.329 31.564
24 5 19.151 41.572 32.661
25 5.2 19.7 42.764 33.732
26 5.4 20.225 43.904 34.756
27 5.7 20.967 45.855 36.245
28 5.8 21.201 46.534 36.73
29 5.9 21.429 47.213 37.211
30 6 21.651 47.883 37.683

Table 1: Total Deformation table with 6 mm mesh size

Figure 3: Equivalent Stress with 6 mm mesh size

Figure 4: Equivalent Stress plot with 6 mm mesh size

  Time [s] Minimum [MPa] Maximum [MPa] Average [MPa]
1 0.2 1.45E-08 2.8924 1.10E-02
2 0.4 2.86E-08 3.554 1.28E-02
3 0.7 2.15E-08 3.0972 1.15E-02
4 1 2.22E-08 1.3008 8.67E-03
5 1.2 2.33E-08 2.9125 1.16E-02
6 1.4 2.38E-08 2.7932 1.10E-02
7 1.7 2.84E-08 2.2971 1.01E-02
8 2 2.57E-08 2.6798 9.35E-03
9 2.2 2.56E-08 2.9847 1.20E-02
10 2.4 2.81E-08 2.7244 1.14E-02
11 2.7 9.51E-08 3.5652 1.36E-02
12 3 2.56E-08 3.3598 1.25E-02
13 3.2 2.42E-08 1.7172 8.72E-03
14 3.4 2.54E-08 4.7929 1.26E-02
15 3.5 2.55E-08 2.023 9.03E-03
16 3.6 2.63E-08 2.9033 1.17E-02
17 3.75 2.88E-08 5.6298 1.39E-02
18 3.875 1.54E-07 5.7189 1.41E-02
19 4 2.94E-08 2.3811 1.05E-02
20 4.2 1.22E-08 3.7059 1.22E-02
21 4.4 1.62E-08 3.2265 1.25E-02
22 4.6 1.59E-08 3.3228 1.26E-02
23 4.8 1.92E-08 1.8436 8.77E-03
24 5 1.44E-07 4.3206 1.43E-02
25 5.2 2.58E-08 1.1162 7.79E-03
26 5.4 2.67E-08 0.81402 7.48E-03
27 5.7 2.58E-08 1.0261 8.43E-03
28 5.8 2.78E-08 3.55 1.16E-02
29 5.9 1.06E-07 3.2869 1.20E-02
30 6 4.58E-08 5.3611 1.35E-02

Table 2: Equivalent Stress table with 6 mm mesh size

Figure 5: Equivalent Strain with 6 mm mesh size

 

Figure 6: Equivalent Strain plot with 6 mm mesh size

  Time [s] Minimum [mm/mm] Maximum [mm/mm] Average [mm/mm]
1 0.2 1.93E-13 1.81E-05 6.80E-08
2 0.4 2.32E-13 2.00E-05 7.78E-08
3 0.7 2.15E-13 1.61E-05 6.85E-08
4 1 2.24E-13 1.38E-05 5.43E-08
5 1.2 2.12E-13 1.75E-05 7.04E-08
6 1.4 2.12E-13 1.76E-05 6.79E-08
7 1.7 2.90E-13 1.62E-05 6.25E-08
8 2 1.64E-13 2.76E-05 6.09E-08
9 2.2 1.60E-13 1.85E-05 7.35E-08
10 2.4 1.66E-13 1.73E-05 7.06E-08
11 2.7 6.88E-13 1.95E-05 8.24E-08
12 3 2.05E-13 1.81E-05 7.48E-08
13 3.2 2.17E-13 1.06E-05 5.36E-08
14 3.4 1.96E-13 2.58E-05 7.54E-08
15 3.5 2.15E-13 1.20E-05 5.59E-08
16 3.6 1.98E-13 2.18E-05 7.12E-08
17 3.75 2.25E-13 3.11E-05 8.34E-08
18 3.875 1.65E-12 3.16E-05 8.45E-08
19 4 2.95E-13 1.41E-05 6.46E-08
20 4.2 2.12E-13 1.94E-05 7.26E-08
21 4.4 2.15E-13 1.87E-05 7.56E-08
22 4.6 2.20E-13 1.87E-05 7.59E-08
23 4.8 2.48E-13 1.21E-05 5.43E-08
24 5 1.23E-12 2.34E-05 8.54E-08
25 5.2 1.59E-13 9.94E-06 4.84E-08
26 5.4 1.74E-13 6.29E-06 4.57E-08
27 5.7 1.91E-13 8.08E-06 5.19E-08
28 5.8 2.22E-13 2.24E-05 7.06E-08
29 5.9 8.37E-13 2.10E-05 7.19E-08
30 6 4.74E-13 3.44E-05 8.21E-08

Table 3: Equivalent Strain table with 6 mm mesh size

Case 2: 5mm mesh size 

  • Setup: A new Static Structural study was created in ANSYS Workbench.
  • Boundary conditions: Structural steel was applied as the material.
  • Frictional contact is established between the small and the large gear.
  • The gears are secured using revolute joints.
  • Mesh: A mesh size of 5 mm is chosen for all bodies and then a finer mesh of 1.75 mm is chosen for certain surfaces where refinement is required using face sizing.
  • Loads: A moment of 100 Nmm was applied and an angular displacement of 120mm in 6 steps was defined to replicate the rotation of the gears.
  • Results: The mesh is generated and Stress, Strain, and Deformation are chosen as the solutions to be evaluated. The results are tabulated in the results section of the report. 

 

Figure 7: Total Deformation with 5 mm mesh size

 

Figure 8: Total Deformation plot with 5 mm mesh size

  Time
[s]
Minimum [mm] Maximum [mm] Average [mm]
1 0.2 0.87249 1.8939 1.4199
2 0.4 1.7439 3.7856 2.8426
3 0.7 3.0467 6.6136 4.982
4 1 4.3412 9.4236 7.0755
5 1.2 5.1978 11.283 8.4679
6 1.4 6.048 13.129 9.8656
7 1.7 7.3093 15.866 11.958
8 2 8.5505 18.561 14.002
9 2.2 9.3652 20.329 15.345
10 2.4 10.168 22.073 16.687
11 2.7 11.35 24.637 18.681
12 3 12.5 27.134 20.642
13 3.2 13.248 28.758 21.915
14 3.4 13.98 30.346 23.166
15 3.5 14.339 31.127 23.793
16 3.6 14.695 31.898 24.412
17 3.75 15.219 33.036 25.335
18 3.875 15.648 33.968 26.1
19 4 16.07 34.883 26.861
20 4.2 16.728 36.312 28.03
21 4.4 17.366 37.698 29.18
22 4.6 17.983 39.037 30.31
23 4.8 18.579 40.329 31.423
24 5 19.151 41.572 32.515
25 5.2 19.7 42.764 33.582
26 5.4 20.225 43.904 34.6
27 5.7 20.967 45.855 36.083
28 5.8 21.201 46.534 36.566
29 5.9 21.429 47.213 37.044
30 6 21.651 47.883 37.514

Table 4: Total Deformation table with 5 mm mesh size

 

Figure 9: Equivalent Stress with 5 mm mesh size

 

Figure 10: Equivalent Stress plot with 5 mm mesh size

  Time [s] Minimum [MPa] Maximum [MPa] Average [MPa]
1 0.2 2.87E-08 2.7331 1.13E-02
2 0.4 1.74E-08 3.164 1.34E-02
3 0.7 1.84E-08 2.8986 1.22E-02
4 1 1.79E-08 1.4585 9.24E-03
5 1.2 2.05E-08 4.2867 1.25E-02
6 1.4 2.18E-08 3.7391 1.18E-02
7 1.7 4.59E-08 2.3629 1.08E-02
8 2 1.72E-08 3.8573 9.68E-03
9 2.2 1.75E-08 3.5314 1.22E-02
10 2.4 2.03E-08 2.6755 1.15E-02
11 2.7 6.44E-08 3.676 1.39E-02
12 3 1.41E-08 2.8419 1.20E-02
13 3.2 1.72E-08 1.8842 8.96E-03
14 3.4 1.58E-08 3.2186 1.21E-02
15 3.5 1.77E-08 2.0065 9.42E-03
16 3.6 1.62E-08 3.0559 1.16E-02
17 3.75 1.50E-08 3.6382 1.34E-02
18 3.875 1.52E-07 3.6955 1.36E-02
19 4 3.78E-08 2.4346 1.08E-02
20 4.2 3.72E-08 3.7344 1.28E-02
21 4.4 3.40E-08 4.6338 1.33E-02
22 4.6 3.24E-08 4.7661 1.34E-02
23 4.8 3.79E-08 1.7877 8.73E-03
24 5 9.31E-08 5.166 1.51E-02
25 5.2 1.31E-08 1.1594 7.72E-03
26 5.4 1.44E-08 0.98863 7.44E-03
27 5.7 1.78E-08 1.1724 8.55E-03
28 5.8 1.78E-08 2.926 1.16E-02
29 5.9 7.38E-08 2.8749 1.19E-02
30 6 5.88E-08 4.1749 1.33E-02

Table 5: Equivalent Stress table with 5 mm mesh size

 

Figure 11: Equivalent Strain with 5 mm mesh size

 

Figure 12: Equivalent Strain plot with 5 mm mesh size

  Time [s] Minimum [mm/mm] Maximum [mm/mm] Average [mm/mm]
1 0.2 1.67E-13 1.70E-05 6.90E-08
2 0.4 2.35E-13 1.80E-05 8.11E-08
3 0.7 1.96E-13 1.67E-05 7.30E-08
4 1 2.02E-13 1.52E-05 5.74E-08
5 1.2 1.94E-13 2.42E-05 7.49E-08
6 1.4 1.98E-13 2.32E-05 7.20E-08
7 1.7 2.60E-13 1.57E-05 6.64E-08
8 2 1.82E-13 3.44E-05 6.23E-08
9 2.2 1.67E-13 2.03E-05 7.39E-08
10 2.4 1.70E-13 1.81E-05 7.08E-08
11 2.7 8.17E-13 2.09E-05 8.45E-08
12 3 7.17E-14 1.59E-05 7.16E-08
13 3.2 8.69E-14 1.10E-05 5.52E-08
14 3.4 8.04E-14 1.94E-05 7.31E-08
15 3.5 8.97E-14 1.21E-05 5.89E-08
16 3.6 8.31E-14 1.90E-05 7.07E-08
17 3.75 7.57E-14 2.07E-05 8.06E-08
18 3.875 1.49E-12 2.02E-05 8.17E-08
19 4 2.08E-13 1.42E-05 6.67E-08
20 4.2 2.38E-13 1.96E-05 7.66E-08
21 4.4 2.42E-13 2.53E-05 8.02E-08
22 4.6 2.55E-13 2.61E-05 8.05E-08
23 4.8 2.77E-13 1.16E-05 5.32E-08
24 5 1.13E-12 2.69E-05 9.07E-08
25 5.2 2.35E-13 9.40E-06 4.78E-08
26 5.4 2.42E-13 6.76E-06 4.57E-08
27 5.7 2.21E-13 8.59E-06 5.27E-08
28 5.8 2.00E-13 1.81E-05 7.02E-08
29 5.9 8.99E-13 1.70E-05 7.12E-08
30 6 4.80E-13 2.67E-05 8.02E-08

Table 6: Equivalent Strain table with 5 mm mesh size

Case 3: 4mm mesh size 

  • Setup: A new Static Structural study was created in ANSYS Workbench.
  • Boundary conditions: Structural steel was applied as the material.
  • Frictional contact is established between the small and the large gear.
  • The gears are secured using revolute joints.
  • Mesh: A mesh size of 4 mm is chosen for all bodies and then a finer mesh of 1.75 mm is chosen for certain surfaces where refinement is required using face sizing.
  • Loads: A moment of 100 Nmm was applied and an angular displacement of 120mm in 6 steps was defined to replicate the rotation of the gears.
  • Results: The mesh is generated and Stress, Strain, and Deformation are chosen as the solutions to be evaluated. The results are tabulated in the results section of the report. 

 

Figure 13: Total Deformation with 4 mm mesh size

 

Figure 14: Total Deformation plot with 4 mm mesh size

  Time
[s]
Minimum [mm] Maximum [mm] Average [mm]
1 0.2 0.87249 1.8939 1.4064
2 0.4 1.7439 3.7856 2.8156
3 0.7 3.0467 6.6136 4.9349
4 1 4.3412 9.4236 7.0084
5 1.2 5.1978 11.283 8.3876
6 1.4 6.048 13.129 9.7721
7 1.7 7.3093 15.866 11.845
8 2 8.5505 18.561 13.87
9 2.2 9.3652 20.329 15.2
10 2.4 10.168 22.073 16.529
11 2.6 10.959 23.79 17.848
12 2.8 11.737 25.477 19.163
13 3 12.5 27.134 20.447
14 3.2 13.248 28.758 21.709
15 3.4 13.98 30.346 22.948
16 3.5 14.339 31.127 23.569
17 3.6 14.695 31.898 24.183
18 3.75 15.219 33.036 25.098
19 3.875 15.648 33.968 25.856
20 4 16.07 34.883 26.61
21 4.2 16.728 36.312 27.769
22 4.4 17.366 37.698 28.908
23 4.7 18.284 39.689 30.581
24 5 19.151 41.572 32.213
25 5.2 19.7 42.764 33.271
26 5.4 20.225 43.904 34.281
27 5.7 20.967 45.855 35.751
28 5.8 21.201 46.534 36.23
29 5.9 21.429 47.213 36.704
30 6 21.651 47.883 37.171

Table 7: Total Deformation table with 4 mm mesh size

 

Figure 15: Equivalent Stress with 4 mm mesh size

 

Figure 16: Equivalent Stress plot with 4 mm mesh size

  Time [s] Minimum [MPa] Maximum [MPa] Average [MPa]
1 0.2 1.89E-08 2.9691 1.08E-02
2 0.4 2.99E-08 3.5139 1.29E-02
3 0.7 2.05E-08 2.8939 1.17E-02
4 1 1.84E-08 1.401 8.92E-03
5 1.2 2.29E-08 3.6063 1.17E-02
6 1.4 2.35E-08 2.9494 1.12E-02
7 1.7 5.20E-08 2.5708 1.02E-02
8 2 1.46E-08 1.6464 8.72E-03
9 2.2 2.03E-08 2.6424 1.13E-02
10 2.4 2.49E-08 2.7542 1.08E-02
11 2.6 3.10E-08 4.2028 1.26E-02
12 2.8 5.92E-08 4.2102 1.30E-02
13 3 1.59E-08 3.2058 1.16E-02
14 3.2 1.32E-08 2.0739 8.77E-03
15 3.4 2.09E-08 3.2896 1.17E-02
16 3.5 1.58E-08 1.8285 9.23E-03
17 3.6 2.15E-08 3.0516 1.12E-02
18 3.75 1.50E-08 3.6402 1.29E-02
19 3.875 1.52E-07 3.6972 1.31E-02
20 4 4.02E-08 2.0274 1.04E-02
21 4.2 3.70E-08 4.3732 1.22E-02
22 4.4 3.69E-08 3.4684 1.22E-02
23 4.7 3.65E-08 2.8919 1.16E-02
24 5 1.20E-07 3.8768 1.39E-02
25 5.2 2.82E-08 1.0241 7.51E-03
26 5.4 2.93E-08 0.87847 7.25E-03
27 5.7 2.93E-08 1.2209 8.22E-03
28 5.8 2.65E-08 3.7525 1.13E-02
29 5.9 6.70E-08 3.5052 1.15E-02
30 6 3.83E-08 5.3843 1.29E-02

Table 8: Equivalent Stress table with 4 mm mesh size

 

Figure 17: Equivalent Strain with 4 mm mesh size

 

Figure 18: Equivalent Strain plot with 4 mm mesh size

  Time [s] Minimum [mm/mm] Maximum [mm/mm] Average [mm/mm]
1 0.2 1.80E-13 1.84E-05 6.56E-08
2 0.4 2.13E-13 1.94E-05 7.73E-08
3 0.7 2.28E-13 1.67E-05 6.97E-08
4 1 2.47E-13 1.36E-05 5.51E-08
5 1.2 2.31E-13 2.11E-05 7.06E-08
6 1.4 2.38E-13 1.83E-05 6.75E-08
7 1.7 4.11E-13 1.72E-05 6.32E-08
8 2 1.58E-13 2.25E-05 5.55E-08
9 2.2 1.45E-13 1.71E-05 6.77E-08
10 2.4 1.50E-13 1.71E-05 6.51E-08
11 2.6 1.84E-13 2.33E-05 7.53E-08
12 2.8 6.95E-13 2.22E-05 7.71E-08
13 3 1.86E-13 1.72E-05 6.88E-08
14 3.2 2.09E-13 1.23E-05 5.40E-08
15 3.4 1.93E-13 1.93E-05 7.06E-08
16 3.5 2.11E-13 1.15E-05 5.70E-08
17 3.6 2.02E-13 1.90E-05 6.81E-08
18 3.75 1.81E-13 2.08E-05 7.72E-08
19 3.875 1.45E-12 2.07E-05 7.83E-08
20 4 2.50E-13 1.42E-05 6.36E-08
21 4.2 2.29E-13 2.33E-05 7.29E-08
22 4.4 2.36E-13 2.05E-05 7.41E-08
23 4.7 2.48E-13 1.78E-05 7.09E-08
24 5 1.13E-12 2.28E-05 8.31E-08
25 5.2 2.63E-13 8.50E-06 4.60E-08
26 5.4 2.66E-13 6.60E-06 4.39E-08
27 5.7 2.38E-13 7.66E-06 4.97E-08
28 5.8 2.14E-13 2.34E-05 6.81E-08
29 5.9 9.63E-13 2.21E-05 6.89E-08
30 6 3.33E-13 2.74E-05 7.74E-08

Table 9: Equivalent Strain table with 4 mm mesh size

Results

What is grid dependency?

As a fundamental rule in FEA, the finer the mesh the more accurate the result. This rule comes with certain conditions. If the mesh is too coarse, then the results are fairly inaccurate when compared to those of a fine mesh. However, having an overly fine mesh means excessive processing times. When the mesh goes from coarse to fine, it reaches a point of refinement where the difference between the previous mesh and the current mesh is almost zero. The process of determining this optimum mesh by going from coarse to fine is called the grid dependency test.  

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