FINAL INDEPENDENT PROJECT

Aim: -

The study of the behavior of a valve disc having ribs or without ribs under presure conditions is the main aim of this study to find deformation.

Introduction: -

Butterfly valves

• A Butterfly valve is a quarter-turn rotational motion valve, that is used to stop, regulate, and start flow.
• Butterfly valves are easy and fast to open. A 90° rotation of the handle provides a complete closure or opening of the valve. Large Butterfly valves are usually equipped with a so-called gearbox, where the handwheel by gears is connected to the stem. This simplifies the operation of the valve, but at the expense of speed.

Model:-

Objective/Tasks: -

• To create a model of a dics having ribs on its and without ribs then, run a static analysis.
• Compare the results and suggest the best one.

Common analysis settings for all analysis: -

Following are the details of all the analysis: -

Material Selection: -

The material used for all the analyses is Steel Alloy. The properties of the alloy steel are shown in figure .

Figure . Properties of alloy steel.

Mesh Parameters: -

Figure 2 shows the parameters used for the fine mesh. The mesh parameters were the same for all the analysis models.

Figure 2. Mesh parameters.

Case 1: Static Analysis of Disc having Ribs.

Procedure: -

The procedure used for the analysis is as follows

1. Create a sketch of the model with ribs.
2. Start a new study. Under it select Static analysis and name it as the disc without ribs.
3. Apply the Alloy Steel Material
4. Apply the fixtures.
5. Apply the loads
6. Generate a mesh with appropriate parameters.
7. Run the study.

Analysis Setup: -

Model: -

First of all, a sketch was made from the according to dimension. Select static structure analysis.

Fixture: -

The shaft was supposed to be fixed at both ends. Figure 5 shows the fixed geometry on the disc

Loads: -

The pressure was applied to the face of the disc. This means that the direction of the force must be outward i.e. the plate is pushed. A pressure of 72.5 psi is applied which is shown in figure .

Analysis Results: -

The analysis results are obtained in terms of strain, stress, and displacement plots.

Von Misses Stress Plot:

The Von Misses Stress plot for the disc with ribs. It is shown in figure 8. The maximum stress obtained 7927 psi. The maximum stress is obtained at center of the disc.

Shows result of vonmises stress

Displacement Plot:

As the plate is pushed from one side, the displacement is 0.08 mm shown in figure .

displacement

Equivalent Strain Plot:

The equivalent strain plot is shown in figure 9. The maximum strain values is 1.582e-04. The intensity of strain is more at the center of the plate.

strain

Case 2: Static Analysis of disc without ribs.

Procedure: -

The procedure used for the analysis is as follows

1. Create a sketch of the model without ribs.
2. Start a new study. Under it select Static analysis and name it as the disc without ribs.
3. Apply the Alloy Steel Material
4. Apply the fixtures.
5. Apply the loads
6. Generate a mesh with appropriate parameters.
7. Run the study.

Analysis Setup: -

Model: -

First of all, a sketch was made from the according to dimension. Select static structure analysis.

Fixture: -

The shaft was supposed to be fixed at both ends. Figure 5 shows the fixed geometry on the disc.

Loads: -

The pressure was applied to the face of the disc. This means that the direction of the force must be outward i.e. the plate is pushed. A pressure of 72.5 psi is applied which is shown in figure .

Analysis Results: -

The analysis results are obtained in terms of strain, stress, and displacement plots.

Von Misses Stress Plot:

The Von Misses Stress plot for the disc with ribs. It is shown in figure 8. The maximum stress obtained 7916 psi. The maximum stress is obtained at center of the disc.

Shows result of vonmises stress

Displacement Plot:

As the plate is pushed from one side, the displacement is 0.172 mm shown in figure .

displacement

Equivalent Strain Plot:

The equivalent strain plot is shown in figure 9. The maximum strain values is 1.912e-04. The intensity of strain is more at the center of the plate

strain

Comparison of Results: -

The results are summarized in a tabular form as shown in table 1. The table contains the details about the stress, strain, and displacement of the plates.

Table 1. Comparison of the Analysis results.
Analysis	Max. Von misses Stress (psi)	Max. Displacement (mm)	Max. Equivalent strain (ESTRN)
Disc with ribs	7927	0.08	1.9Xe-4
Disc without ribs	7916	0.172	1.5Xe-4

Observation: -

From table 1, it is clear that the stress and strain have decreased in the disc with ribs, whereas the displacement have decreased. It can also be seen providing the ribs increase the strength of the disc.

Conclusion: -

In this study, two models of a disc were created. One without ribs and another one with ribs. The static analysis was done on both of them having a 72.5 psi pressure on one faces. The results obtained showed that the disc with ribs had less stress and strain than the plate with one hole. While displacement the is less than that of the disc without ribs. From a purely analytical point of view, the disc provided ribs save the material and manufacturing cost.