Analysis of Stress Concentration on a Plate with hole using ANSYS Workbench

OBJECTIVE:

To design and simulate the given models of plates with the hole using ANSYS Workbench. The results of the simulation between the two cases must be compared with respect to deformation and maximum stress.

PROCEDURE FOR CASE SETUP:

For case 1:

1. Open ANSYS>>Drag and drop Static Structural module in the project schematic window.

2. In the engineering data the default material loaded is structural steel. The same material is going to be used for the simulation.

3. In the geometry tab, the model is designed using space claim. The designed model is shown in the figure below.

The geometry extruded after giving the pull option is shown below. The construction lines are deleted before giving the pull option. The thickness given is 30 mm. The surface holes are deleted before giving the extrude option.

4. Close the geometry tab and open the model tab to do meshing and case setup for the model.

5. The mesh size is chosen as 3.5 mm so that it does not exceed the number of nodes and elements limitation. The mesh method is chosen as the tetrahedron. This is explained in the figures shown below.

6. The final meshed model is shown below.

7. The boundary conditions are defined by fixing the left face of the plate and giving a force of 500 N on the right face. This is shown in the figure below.

8. From the solution option, the results for total deformation and equivalent stress are requested.

9. From the analysis settings, hit on solve to start the simulation. 

For case 2:

1. Open ANSYS>>Drag and drop Static Structural module in the project schematic window.

2. In the engineering data the default material loaded is structural steel. The same material is going to be used for the simulation.

3. In the geometry tab, the model is designed using space claim. The designed model is shown in the figure below.

The geometry extruded after giving the pull option is shown below. The construction lines are deleted before giving the pull option. The thickness given is 30 mm. The surface holes are deleted before giving the extrude option.

4. Repeat steps 4-5 as in case 1 setup.

5. The final meshed model is shown in the figure below.

6. Repeat steps 7-9 as in case 1 setup.

RESULTS AND DISCUSSION:

 1. The following results are obtained for total deformation for the two cases.

Case 1:

Case 2:

Comparison of total deformation:

From the above contours, it can be inferred that the total maximum deformation for case 1 is 0.00027487 mm and for the case total maximum deformation for case 2 is 0.00029718 mm. The total deformation is slightly higher for case 2 when compared to case 1. The difference is 

 2. The following results are obtained for equivalent stress for the two cases.

Case 1:

Case 2:

Comparison of equivalent stress:

From the above contour, it can be seen that the maximum equivalent stress obtained for case 1 and case 2 are 0.60589 MPa and 0.58402 MPa respectively. The value of the maximum equivalent stress is higher for case 1 when compared to case 2.

The final tabulated results are shown below:

CONCLUSION:

From the analysis, it can be concluded that the maximum stress developed for a plate with multiple holes is lesser which is 0.58402 MPa. The maximum deformation is higher for the same which is 0.00029718 mm. This is because the stress concentration is relatively smooth for a plate with multiple holes than with a single hole.

All the objectives are satisfied as given in the challenge.

Selection of Design from the Analysis point of view:

From the analysis, it can be inferred that the maximum stress (0.58402 MPa) is lesser for a plate with multiple holes. Therefore, the plate with multiple holes can be chosen. This performs well since it develops lesser stress when compared to case 1 results. (this is due to higher stress concentration in case 1)

Selection of Design from the Manufacturing point of view:

From the manufacturing point of view, a plate with a single hole can be chosen. This is because the hole is created using the drilling operations. For creating one hole the time required is less when compared to a plate with three holes. Therefore, the manufacturing cost can be reduced considerably in the case of a plate with a single hole.  Also, drilling multiple holes is difficult from a manufacturing perspective and requires considerable effort and time.