Buckling Analysis
Aim: Design and analysis of Buckling Phenomenon in a Cyclonic Separator Stand.
Objective:
The objective of this challenge is to perform buckling analysis on a cyclonic separator stand using the simulation module of Solidworks and to identify the buckling factor of safety. The second part of this challenge is to run a design study to identify the optimum position of the stiffener and maximize the buckling factor of safety.
Figure 01: Cyclonic Separator stand without rib.
Figure 02: Cyclonic Separator stand with rid.
Tools used:
Solidworks Simulation module
Microsoft Excel
Glossary:
1. Buckling: Buckling is the principal mode of failure in long and slender members where the failure occurs not by direct compression, instead of by lateral deflection. The load at which this occurs is called critical load Pcr.
2. Buckling Factor of safety: The ratio between Critical load and the load applied is called Buckling Factor of Safety. [Buckling Factor of Safety=Pcr/Papplied)
3. Cyclonic Separator: Cyclone separators or simply cyclones are separation devices (dry scrubbers) that use the principle of inertia to remove particulate matter from flue gases. Cyclone separators are one of many air pollution control devices known as pre-cleaners since they generally remove larger pieces of particulate matter. (Source: Energy Education)
Pre-requisites:
The cyclonic separator modeled in Solidworks using the Solid modeling tools (Source: Skill-Lync).
Experimental Setup:
Experiment 1: Simple buckling analysis on a cyclonic separator stand with no stiffener
Experiment 2: Simple buckling analysis on a cyclonic separator stand with a stiffener in an arbitrary position (2000mm offset in this case)
Experiment 3: Design study to optimize the location of the stiffener for maximum Buckling Factor of Safety
Boundary conditions (Same for all 3 tests):
Equipment type = Cyclone Separator Stand
Material = Alloy Steel (See figure 3 for Material properties)
Fixture = 4 ends of the legs of the stand are fixed
Mesh size = 15 mm
Load applied = 150000 N
Figure 03: Material Properties of Alloy steel
Experiment 1: Simple buckling analysis on a cyclonic separator stand with no stiffener
Setup: A new buckling analysis study was created in Solidworks simulation after downloading the cyclonic separator stand assembly model and suppressing the cyclonic separator equipment.
Boundary conditions: Alloy steel was applied as the material; The bottom of the 4 feet are fixed and a downward load of 150kN is applied on the top face of the
stand.
Mesh: A mesh size of 15 mm is chosen and applied.
Results: The mesh is applied and the simulation is run. The plots are generated and the buckling factor of safety is noted. In this test, the buckling factor of safety is found to be 9.3442
Figure 04: Cyclonic Separator Stand without rib (4 feet are fixed and a downward load of 150kG is applied on the top face of the stand)
Figure 5: Result of buckling analysis on Cyclonic Separator Stand without rib
Experiment 2: Simple buckling analysis on a cyclonic separator stand with a stiffener in an arbitrary position
Setup: A new buckling analysis study was created in Solidworks simulation after saving the cyclonic separator stand assembly model as a part file drawing a 75mm thick rid offset at 2000 mm from the top of the stand.
Boundary conditions: Alloy steel was applied as the material; The bottom of the 4 feet are fixed and a downward load of 150kN is applied on the top face of the
stand.
Mesh: A mesh size of 15 mm is chosen and applied.
Results: The mesh is applied and the simulation is run.
The plots are generated and the buckling factor of safety is noted. In this test, the buckling factor of safety is found to be 9.8672.
Figure 6: Cyclonic Separator Stand with rib (4 feet are fixed and a downward load of 150kG is applied on the top face of the stand)
Figure 7: Result of buckling analysis on Cyclonic Separator Stand with rib at an offset of 2000 mm
Experiment 3: Design study to optimize the location of the stiffener for maximum Buckling Factor of Safety
• Setup: A new design study was created in Solidworks Simulation
• Boundary conditions: There are 3 conditions that need to be defined.
• Variable - The offset length of the stiffener is varied from 200 mm to 2000 mm in increments of 200 mm.
• Constraints - The Buckling Factor of Safety was set at a minimum of 25.
• Goals - The maximum buckling factor of safety is to be determined.
• Mesh: A mesh size of 15 mm is retained from the previous test.
• Results: The conditions of the design study are applied and the simulation runs through each of the scenarios to determine the optimum offset of the rib from the top of the stand. The results of the design study are tabulated as follows.
Figure 8: Result of buckling analysis on Cyclonic Separator Stand with rib at an offset of 2000 mm
Results: Performing the 3 tests in a sequential manner has helped us determine the buckling factor of safety without a stiffener, with a stiffener in an arbitrary location and the optimal location for the stiffener.
Figure 9: Stiffener offset (mm) Vs Buckling factor of safety
Observations:
- Adding a stiffener will increase the factor of safety of the structure as far as buckling analysis is concerned for this cyclonic separator stand.
- For the parameters given in the design study, an offset of 1000mm for the stiffener from the top of the stand seems to be the optimal position of the stiffener if it is to satisfy the preset condition that the Buckling Factor of Safety is greater than 25.