ANALYSIS OF BUCKLING PHENOMENON | SOLIDWORKS SIMULATION | FEA

AIM:

In this project, the main objective is to perform a buckling analysis on a cyclonic separator stand by creating a metallic stiffener on the legs of the stand and run the analysis to find out the change in buckling factor of safety. Once we find the buckling factor of safety, we run a design study for different positions of the stiffener on the stand and find the optimum position for the stiffener and consider that buckling factor of safety

Introduction

In engineering, buckling is the sudden change in the shape of a structural component under loads such as the bowing of a column under compression or the wrinkling of a plate under shear. If a structure is subjected to a gradually increasing load when the load reaches a critical level, a member may suddenly change shape and the structure and component are said to have buckled.

Buckling refers to the loss of stability of a component and is usually independent of material strength. This loss of stability usually occurs within the elastic range of the material.

Theory:

Buckling may occur even though the stresses that develop in the structure are well below those needed to cause failure in the material of which the structure is composed. Further loading may cause significant and somewhat unpredictable deformations, possibly leading to complete loss of the member's load-carrying capacity. However, if the deformations that occur after buckling do not cause the complete collapse of that member, the member will continue to support the load that caused it to buckle. If the buckled member is part of a larger assemblage of components such as a building, any load applied to the buckled part of the structure beyond that which caused the member to buckle will be redistributed within the structure. Some aircraft are designed for thin skin panels to continue carrying load even in the buckled state.

In this study, I have used a cyclone separator stand CAD (Downloaded from the skill-Lync site).

ANALYSIS 1:

1. Performed a buckling analysis on the cyclone separator stand without stiffener

Material Properties
Model type:	Linear elastic isotropic
Material:	Alloy Steel
Elastic Modulus:	2.1e+11 Nm − 22.1e+11 Nm-2
Poisson's Ratio:	0.280.28
Shear Modulus:	7.9e+10Nm − 27.9e+10Nm-2
Mass Density:	7700 kgm^3 −37700 kgm^3
Tensile Strength:	723825600 kgm3723825600 kgm3
Yield Strength:	620422000 Nm−2620422000 Nm-2
Thermal Expansion Coefficient:	1.3e−05K−11.3e-05K-1
Thermal Conductivity:	50 Wm−1⋅K−150 Wm-1·K-1
Specific Heat:	460 J.kg−1⋅K−1460 J.kg-1·K-1

Steps to Analysis 1:

1. Import the Cyclone separator file into Solidworks. It gets imported as an assembly, so suppress all the parts except the stand.
2. New study> choosing buckling study> Rename the study-Analysis without stiffener>Click ok.
3. Define the material used, which in our case is Alloy steel.
4. Fixtures to added. We fix the four-bottom face of the legs of the cyclone separator.
5. Externals Loads to defined: We add the force(N) on the top face of the cyclone separator stand. Force applied: 150KN.
6. Mesh Parameter: Element size: 25 mm; Tolerance: 1.25 mm.

RESULTS:

Buckling Factor of Safety is: 9.3267

Deformation Scale: 60.6767

ANALYSIS 2:

In this analysis, we will create a metallic stiffener (Alloy Steel-Material) of 75mm in length.

We initially run the buckling analysis similar to analysis_1, where a stiffener is placed at a distance of 1000mm and finds the buckling factor of safety for it. This resulting factor of safety will use it as a base for our design study.

Steps to Analysis 2:

1. Import the Cyclone separator file into Solidworks. It gets imported as an assembly, so suppress all the parts except the stand.
2. Use the face of the stand and sketch a square stiffener and extrude 80mm, post which, place the extruded part with offset function to around 900mm (Downwards direction).
3. Choose New study> choosing buckling study> Rename the study-Analysis with stiffener>Click ok.
4. Define the material used, which in our case is Alloy steel.
5. Fixtures to added. We fix the four-bottom face of the legs of the cyclone separator.
6. Externals Loads to defined: We add the force(N) on the top face of the cyclone separator stand. Force applied: 150KN.
7. Mesh Parameter: Element size: 25 mm; Tolerance: 1.25 mm.

RESULTS:

Buckling Factor of Safety is: 25.72410

Deformation Scale: 61.8535

DESIGN STUDY.

The following conditions are involved in the design study.

1. Choose New Study > under that select design study.
2. Under design variable > select the offset distance of 1000mm> ok> under value: Min: 500mm; Max:1600; Step: 100.
3. Under constraints> choose the simulation study> under that choose: Buckling factor of safety > ok > Condition select > greater than.
4. Under goals> select Buckling factor of safety> Goal: Maximize.
5. The final step is to run the simulation.

DESIGN STUDY RESULTS:

From the design, it is found from the first analysis that the buckling factor of safety for cyclone separator stand without support is 9.3669. In the design study, it is obtained that the optimum position to place a stiffener is 900mm from the top of the table and the maximum buckling factor of safety is approximately 27.42765 The maximum buckling factor of safety is duly verified by the result of the design study.

EXCEL SHEET: CLICK HERE FOR DATA FILE

CONCLUSION:

Hence the buckling factor of safety of the cyclone separator stands without support is 9.3669. The optimum position of stiffener to obtain maximum buckling factor of safety is 900mm from the tabletop. The maximum buckling factor of safety is approximately 27.42675.