Aim: -

The study of the change in the buckling factor of safety on the addition of a metallic stiffener to a cyclonic separator stand is the main aim of this work. Another aim of the study is to find the optimum position of the metallic stiffener on the legs of the stand.

Introduction: -

A cyclonic separator is used to remove unwanted particulate matter from the air or gas. It uses the principle of cyclone separation where the matter is removed by using vortex separation. The rotational effect and gravity are used to remove the solids from fluids. A high-speed rotating (air) flow is established within a cylindrical or conical container called a cyclone. In a conical system, as the rotating flow moves towards the narrow end of the cyclone, the rotational radius of the stream is reduced, thus separating smaller and smaller particles.

Buckling is the sudden change in the shape of an element and that element is said to be buckled. Whenever an element is subjected to gradually increasing load, there might be a time when the structure may suddenly change its shape. At that time, the structure is said to be buckled. The buckling may also happen due to the internal stress produced by the load. The stress might very well be below the allowed stress but still, the element might get buckled. Thus, the buckling analysis is generally done on the element.

Objective: -

1. To simulate a buckling analysis of the cyclonic separator stand.
2. To create a metallic stiffener for the legs of cyclonic separator stand. To analyze the separator with the metallic stiffener and compare the buckling factor of safety.
3. To find the optimum position of the metallic stiffener by doing a design study.

Analysis Details and setup: -

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 1.

Figure 1. 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.

Analysis 1: - Buckling analysis of the cyclonic separator stand without metallic stand

The procedure used for the analysis is as follows

1. Create a part file for the cyclonic separator stand from the STEP file.
2. Start a new study. Under it select Buckling analysis and name No support cyclone separator.
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.

Model: -

First of all, from the STEP file, all the parts except the stand were suppressed as the analysis was to be done of the stand only. Figure 3 shows the model of the cyclone separator stand.

Figure 3. Cyclone separator stand.

Fixture: -

The stand will be on the ground and thus the bottom faces of the legs are fixed. Figure 4 shows the fixed geometry of the model.

Figure 4. The fixed geometries of the model.

Loads: -

The cyclone separator will be loaded with a load of 120000 N on its top surface. It is shown in figure 5.

Figure 5. A 120000N load applied to the separator.

Mesh: -

The mesh was done using the parameters shown earlier. Figure 6 shows the meshed model of the cyclonic separator stand.

Figure 6. Meshed model of the cyclonic separator.

Results: -

The effect of the 120000 N load on the structure is shown as the amplitude plot here. The amplitude of the buckling is shown in figure 7. The maximum and minimum values of amplitude are 3.854e-03 and 0.00e+00 respectively. The animation also shows the variation with time. The buckling factor of safety is used to determine the structural capacity in buckling. Generally, the buckling factor of safety should be greater than 3. In our case, as shown in figure 8, the factor of safety for buckling is 11.68 (>3). Thus, it is safe.

Figure 7. Buckling amplitude of the Cyclone separator.

Figure 8. Buckling Factor of Safety.

Observation: -

From the results of the analysis, we observed that the buckling factor of safety is 11.68 which shows that the cyclone separator will not buckle at a load of 120000N. The load must be increased significantly for the cyclone separator stand to buckle.

Analysis 2: - Buckling analysis of the cyclonic separator stand with a metallic stand

The procedure used for the analysis is as follows

1. Create a part file for the cyclonic separator stand from the STEP file.
2. Create the Metallic Stiffener for the cyclonic separator.
3. Start a new study. Under it select Buckling analysis and name Buckling analysis of no support cyclone separator with metallic stiffener.
4. Apply the Alloy Steel Material
5. Apply the fixtures.
6. Apply the loads
7. Generate a mesh with appropriate parameters.
8. Run the study.
9. Compare the results with previous analysis.

Model: -

The metallic stiffener was created using these steps

1. Sketch a geometry for the stiffener on the top plane of the model.
2. Extrude the geometry to 40 mm with an offset of 750 mm from the top plane.

The metallic stiffener attached to the legs of the cyclone separator stand is shown in figure 9.

Figure 9. Cyclonic separator stands with a metallic stiffener attached to its legs.

Fixture: -

The stand will be on the ground and thus the bottom faces of the legs are fixed the same as in the earlier analysis. Figure 10 shows the fixed geometry of the model.

Figure 10. The fixed geometries of the model.

Loads: -

The cyclone separator will be loaded with a load of 120000 N on its top surface. It is shown in figure 11.

Figure 11. A 120000N load applied to the separator.

Mesh: -

The mesh was done using the parameters shown earlier. Figure 12 shows the meshed model of the cyclonic separator stand.

Figure 12. Meshed model of the cyclonic separator with the metallic stand.

Results: -

The effect of the 120000 N load on the structure is shown as the amplitude plot here. The amplitude of the buckling is shown in figure 13. The maximum and minimum values of amplitude are 3.835e-03 and 0.00e+00 respectively. The animation also shows the variation with time. The buckling factor of safety is used to determine the structural capacity in buckling. Generally, the buckling factor of safety should be greater than 3. In our case, as shown in figure 14, the factor of safety for buckling is 20.226 (>3). Thus, it is safe.

Figure 13. Buckling amplitude of the Cyclone separator with the metallic stiffener.

Figure 14. Buckling Factor of Safety.

Observations: -

When the metallic stiffener was attached to the cyclonic separator stand, the amplitude remains the same. But there is a significant change in the buckling factor of safety. The change can be seen in table 1 and figure 7 & 13.

Table 1: Comparison of both the Analysis.

Simulation	Amplitude		Buckling Factor of Safety
	Max	Min
Without Stiffener	3.854e-03	0	11.68
With Stiffener	3.835e-03	0	20.226

Analysis 3: - Optimization of the cyclonic separator with the metallic stiffener analysis

The buckling factor of safety can again be increased by doing a design study of the previous analysis.

Procedure:-

1. Select a new Study.
2. Select Design study.
3. Add Parameters to the variable section.
4. Select the appropriate variable with the minimum, maximum, and step values.
5. Add constraints to the constraint section.
6. Add the goal of the study.
7. Run the study.

Design Study settings: -

As seen earlier, the addition of the metallic stiffener increased the buckling factor of safety but it can easily be optimized. The inputs which can be varied to its optimal value are listed below.

1. The thickness of the stiffener (Extrude length).
2. The position of the stiffener (Distance from the top plane or the upper face of the separator).
3. The material of stiffener and separator.
4. The Force acting on the top face.
5. Mesh (Finer mesh).

Here, out of all the inputs, three can be optimized without changing much from the other analysis which is shown in figure 15.

Figure 15. Variables which can be optimized.

But these variables will result in more than 1500 scenarios. This requires more computational time and power. As per the problem statement, we need to only optimize the position of the stiffener. This also resulted in the simulation of 203 scenarios.

Variables: -

The variable to be optimized was the position of the stiffener on the legs of the stand. The position was to be optimized with a minimum value or initial step of 40 mm and maximum value or last step of 2040mm. The scenarios were created with a step value of 10mm.

Figure 16. Variable of the study.

Constraints: -

The constraint on the optimization study was of the buckling factor of safety. The buckling factor of safety was to be greater than 20. The buckling factor of safety sensor was taken of the analysis 2 study. This is shown in figure 17.

Figure 17. Constraints of the study.

Goals: -

The optimization must have a goal as there might be many cases where the buckling factor of safety will be more than 20. So, the goal of the study is to maximize the buckling factor of safety. It is shown in figure 18.

Figure 18. The goal of the study.

Summary: -

The summary of the analysis settings is shown in figure 19.

Figure 19. Summary of the analysis settings.

Results: -

The results obtained are as shown in figure 20.

Figure 20. Design study result.

The optimal position in the model is shown in figure 21.

Figure 21. Optimal Position of the metallic stiffener.

Observation: -

The scenarios between 71(740mm) and 112(1150mm) showed the buckling factor of safety greater than 20. The optimal result was found to be 950mm for 120000N load and 40 mm thickness with alloy steel as the material of the stiffener. The buckling factor of safety was found to be 21.587080.

The buckling factor of safety can be increased more by changing the material and thickness of the metallic stiffener.

Conclusion: -

We did a buckling analysis for a cyclonic separator stand and found the buckling factor of safety to be 11.68. It was increased to 20.228 by the addition of a metallic stiffener to its legs of 40mm thickness at a distance of 750 mm from the top surface. An optimization design study showed that the buckling factor of safety can be further be increased to 21.587080 by changing the metallic position to 950 mm from the top.