Mastering Buckling Analysis in SolidWorks: A Complete Guide

Welcome back to our blog series on Finite Element Analysis (FEA) using SolidWorks! Today, we’ll dive into a crucial topic in structural analysis: Buckling. By the end of this blog, you’ll understand what buckling is, how it differs from bending, and how to perform a buckling analysis in SolidWorks. 

Let’s get started! 

What is Buckling? 

Buckling is a sudden change in shape that occurs when a structural member (like a column or a beam) is subjected to a compressive load. A common example of buckling is the bowing of a column under compression, or the wrinkling of a plate under shear stress. 

Unlike bending, which develops progressively as a load increases, buckling is a state of instability. It happens suddenly when the load reaches a critical level, known as the critical load or Euler’s critical load. The key distinction is that buckling results from instability in the structure rather than material failure. 

Bending vs. Buckling 

Bending: Stress develops gradually in an object under load. The object deforms continuously as the load is applied. 

Buckling: Instability occurs when the compressive force reaches a critical threshold, causing a sudden deformation. 

Simple Experiment to Visualize Buckling 

Try this simple experiment to understand the difference between bending and buckling. Take a steel ruler and fix it horizontally, like a beam. Apply a small weight, and you’ll see the ruler bending progressively as the load increases. 

Now, hold the ruler vertically, like a column. As you increase the load on top, nothing much happens—until suddenly, at a critical load, the ruler snaps to the side, buckling. This demonstrates the abrupt nature of buckling compared to bending. 

The Influence of Fixtures on Buckling 

The way a structure is supported can dramatically affect how it buckles. Let’s consider three common types of fixtures: 

1. Pinned Ends: These allow rotation but prevent translation. This setup gives a moderate resistance to buckling. 
2. Fixed Ends: Both rotation and translation are restricted, offering the most resistance to buckling. 
3. Free Ends: No restrictions are present, and buckling occurs with the least resistance. 

Different combinations of these fixtures create various buckling shapes, which is important to consider in the design phase. 

Performing a Buckling Analysis in SolidWorks 

Now that you understand the theory, let’s move into SolidWorks to run a buckling analysis. 

Step 1: Open the Model 

For this example, we’ll analyze the legs of a cyclonic separator. The goal is to determine if the four supporting legs will buckle under a given load. 

1. Open the SolidWorks model of the cyclonic separator stand. 
2. Make sure you have the Simulation Add-In activated. If not, go to SolidWorks Add-Ins and enable it. 

Step 2: Set Up the Buckling Study 

1. New Study: Go to the Simulation tab and create a New Study. Select Buckling Analysis from the list. 
2. Simplify the Model: The assembly consists of four separate parts—the stand and three parts of the separator itself. For the buckling analysis, we only need the stand. Suppress the other parts to reduce computational load and simplify the analysis. 

Step 3: Apply Material Properties 

1. Assign a material to the stand by right-clicking on the part and selecting Apply/Edit Material. 
2. Select Steel or another appropriate material. Make sure you have the key properties for buckling analysis: Elastic Modulus, Poisson’s Ratio, and Mass Density. 

Step 4: Apply Fixtures and Loads 

1. Fixtures: Fix the four legs of the stand using the Fixed Geometry option. This simulates how the legs are anchored to the ground. 
2. Loads: Apply a compressive force of 200,000 Newtons downward on the top of the stand. Ensure the load direction is correct. 

Step 5: Mesh the Model 

To ensure accurate results, apply a fine mesh to the four legs, where most deformation will occur, and a coarser mesh to the top plate. Use the Mesh Control feature to refine the mesh on specific areas. 

1. Select the faces of the four legs and apply a 9 mm mesh. 
2. Create a general mesh for the entire model. 

Step 6: Run the Simulation 

Now, you’re ready to run the buckling analysis! Click Run to start the simulation. Depending on your mesh and model complexity, it might take a few minutes to complete. 

Step 7: Review the Results 

Once the simulation is complete, you can visualize the buckling mode of the stand. SolidWorks shows the deformed shape and allows you to animate it for better understanding. 

You can also generate a buckling factor of safety report to determine how close the applied load is to causing buckling. In this case, if the factor of safety is 7, it means the load would need to be increased by seven times for buckling to occur. 

 Understanding the Buckling Factor of Safety 

The buckling factor of safety is crucial for evaluating structural stability. As a general rule of thumb, the buckling factor of safety should be greater than 3 to ensure the structure is safe under normal loading conditions. 

To increase the buckling factor of safety, you can make design changes such as adding stiffeners to the structure. These can be placed along the vertical or horizontal axes of the support legs to increase resistance to buckling. 

Generating a Buckling Analysis Report 

SolidWorks allows you to generate a detailed report of your buckling analysis: 

1. Go to the Results tab and click Generate Report. 
2. Customize the report to include information like the designer’s name, company details, and all relevant simulation data. 
3. The report will include a 3D model image, buckling mode shapes, load factors, and other critical results—perfect for documentation or presentations. 

Summary of Key Points 

• Buckling is a sudden change in the shape of a structure under compressive load, leading to failure. It’s distinct from bending, which is a progressive deformation. 
• Buckling depends on both the critical load and the fixture type used on the structure. 
• In SolidWorks, you can perform a buckling analysis by defining the material properties, applying proper fixtures and loads, meshing the model, and running the simulation. 
• The buckling factor of safety tells you how much more load the structure can handle before it buckles. 

That wraps up our discussion on buckling and how to perform a buckling analysis in SolidWorks. In our next session, we’ll dive deeper into advanced simulation techniques for more complex structural evaluations. 

Happy simulating! 

This blog is part of our ongoing series on FEA Simulations using SolidWorks. If you missed the previous posts, check them out here.  

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