> ## Documentation Index
> Fetch the complete documentation index at: https://docs.ntop.com/llms.txt
> Use this file to discover all available pages before exploring further.

# How to run a buckling analysis

## Objective:

Learn how to perform a Buckling Analysis.

<Note>
  This article uses Simulation/Optimization and both of them in nTop have two requirements: FE Mesh and Boundary Conditions (BCs). Follow the instructions in the links below to prepare your model for simulation.

  **FE Mesh**

  * [How to create an FE Volume Mesh](/help-articles/knowledge-base/meshing-workflows/how-to-create-an-fe-volume-mesh)
  * [How to create a Simulation Model](/help-articles/knowledge-base/structures/how-to-create-a-simulation-model)

  **Boundary Conditions (BCs)**

  * [How to select boundaries of an FE Mesh - FE Boundary by Flood Fill](/help-articles/knowledge-base/structures/how-to-select-boundaries-of-an-fe-mesh-fe-boundary-by-flood-fill)
  * [How to choose boundaries of an FE Mesh - FE Boundary by Body](/help-articles/knowledge-base/structures/how-to-select-boundaries-using-boundary-by-body)
  * [How to use Boundary Conditions](/help-articles/knowledge-base/structures/how-to-use-boundary-conditions)
  * [How to use a CAD Face in a boundary condition](https://support.ntopology.com/hc/en-us/articles/4609628488083)
</Note>

**1. Run a Buckling Analysis**

* * Add a **Buckling Analysis** block
    * Insert the [Simulation Model](/help-articles/knowledge-base/structures/how-to-create-a-simulation-model) into the Model input
    * Add the [Force BC](https://support.ntopology.com/hc/en-us/articles/360055857533) to the BC List input
    * Press the '**+**' in the BC List to add another input
    * Insert the [Restraint BC](https://support.ntopology.com/hc/en-us/articles/360055857533) into the new input slot

*Boundary conditions must contain a displacement restraint for at least one node. Otherwise, the model isn't fixed in space.*

* * Enter the Maximum Number of modes you wish to calculate.
    * You can bound the Min and Max Eigenvalues, but it will return an error if there are no eigenvalues in that range.

<Note>
  **Note:** This is a ***linear buckling analysis***. All inertial and damping forces are neglected. To get the most accurate results, it is recommended that a *Quadratic* geometric order FE mesh be used with any analysis.
</Note>

* The loads are assumed to be applied slowly until the model reaches a state of equilibrium (static assumption), and the relationship between loads and displacements is assumed to be linear.

![A structure with yellow arrows on top to indicate an applied boundary load. The bottom of the structure has red arrows indicating displacement restraints.](https://files.learn.ntop.com/help-articles/structures/38043830310803.png)

**2. Reading the Results**

Once you run an analysis, a Heads Up Display (HUD) will appear, showing the results. The HUD allows you to toggle through Total displacement and Displacement across the X, Y, and Z axes.

* The result of the buckling simulation ('buckling load factor" property in the block's properties) is a list of factors by which the model's load(s) must be multiplied to reach the critical buckling load for each mode.
* The results are ranked by the intensity of each mode, from high to low.

![A gif showing buckling analysis results. The results move and change as the sliders are adjusted in the HUD.](https://files.learn.ntop.com/help-articles/structures/41633510214675.png)

And that's it! You've successfully run a buckling analysis.

Are you still having issues? Contact the [support team](https://support.ntopology.com/hc/en-us/requests/new), and we'll be happy to help!

## Download the Example file:

* [Example file](https://files.learn.ntop.com/Support%20Article%20Example%20Files/Knowledge%20Base/Simulation/Buckling%20Analysis%20Example.ntop)

## Keywords:

*analysis fea design displacement buckling value how-to eigen*