> ## 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.

# Modal Analysis

<CardGroup cols={2}>
  <Card title="FE Model, Restraints, Integer, Scalar, Scalar" href="#fe-model-restraints-integer-scalar-scalar" />

  <Card title="FE Model, Restraints, Integer, Scalar, Scalar, 1.1.0" href="#fe-model-restraints-integer-scalar-scalar-110" />

  <Card title="FE Model, Restraints, Integer, Scalar, Scalar, 1.2.0" href="#fe-model-restraints-integer-scalar-scalar-120" />

  <Card title="FE Model, Restraints, Integer, Scalar, Scalar, 1.3.0" href="#fe-model-restraints-integer-scalar-scalar-130" />
</CardGroup>

***

## About this Block

**What it does:** Runs an analysis on an [**Simulation Model**](/block-documentation/blocks/structures/model/simulation-model.html) that calculates its natural frequencies (eigenfrequencies) and their corresponding mode shapes.

**Common uses:**

* Understanding the vibrational characteristics of your model.

**Tips:**

* Free modes of vibration calculations don't consider forces. Therefore, we don't need to use them in the boundary conditions.
* Run free-free modal analysis by not providing any Restraints.
* You can bound the minimum and maximum frequencies, but it will return an error if there are no natural frequencies in that range.
* When the calculation is complete, a Head's Up Display (HUD) will appear that allows you to visualize the block's results. The block's visibility must be on to see the results window.
* You can change the min and max values in the colormap by clicking on their values.
* The "Deformation scale" controls the exaggeration of the displacement for visual inspection.
* To access the eigenfrequencies, open the Info Panel > Properties. Scroll down and expand the eigenfrequencies. Drag these into the Notebook to use the values.
* It is recommended to use a Quadratic Geometric order FE Mesh with any analysis to get the most accurate results.

## Example File

Download Example: [Modal Analysis](https://storage.googleapis.com/files-learn/static/ExtendedBlockDocs/modal_buckling_analysis.ntop)
![Modal Analysis](https://storage.googleapis.com/files-learn/static/ExtendedBlockDocs/modal_analysis.png)

***

<h2 id="fe-model-restraints-integer-scalar-scalar">
  FE Model, Restraints, Integer, Scalar, Scalar
</h2>

Calculate the natural frequencies and mode shapes of an FE Model subject to prescribed boundary conditions. This block calculates a specified number of vibration modes. Providing minimum and maximum frequencies bounds the range of frequencies to be returned. Removing the optional Restraints input leads to a free-free Modal Analysis.

### Inputs

| Name            | Type                                                                                | Description                           |
| --------------- | ----------------------------------------------------------------------------------- | ------------------------------------- |
| Model           | [FE Model](../../../../block-documentation/types/fe-model)                          | The finite element model.             |
| Restraints      | [Boundary Condition List](../../../../block-documentation/types/boundary-condition) | The displacement restraints.          |
| Number of modes | [Integer](../../../../block-documentation/types/integer)                            | Maximum number of modes to calculate. |
| Min frequency   | [Scalar](../../../../block-documentation/types/scalar)                              | Lower bound of returned frequencies.  |
| Max frequency   | [Scalar](../../../../block-documentation/types/scalar)                              | Upper bound of returned frequencies.  |

### Outputs

| Type                                                               |
| ------------------------------------------------------------------ |
| [Modal Result](../../../../block-documentation/types/modal-result) |

***

<h2 id="fe-model-restraints-integer-scalar-scalar-110">
  FE Model, Restraints, Integer, Scalar, Scalar, 1.1.0
</h2>

Calculate the natural frequencies and mode shapes of an FE Model subject to prescribed boundary conditions. This block calculates a specified number of vibration modes. Providing minimum and maximum frequencies bounds the range of frequencies to be returned. Removing the optional Restraints input leads to a free-free Modal Analysis.

### Inputs

| Name            | Type                                                                                | Description                           |
| --------------- | ----------------------------------------------------------------------------------- | ------------------------------------- |
| Model           | [FE Model](../../../../block-documentation/types/fe-model)                          | The finite element model.             |
| Restraints      | [Boundary Condition List](../../../../block-documentation/types/boundary-condition) | The displacement restraints.          |
| Number of modes | [Integer](../../../../block-documentation/types/integer)                            | Maximum number of modes to calculate. |
| Min frequency   | [Scalar](../../../../block-documentation/types/scalar)                              | Lower bound of returned frequencies.  |
| Max frequency   | [Scalar](../../../../block-documentation/types/scalar)                              | Upper bound of returned frequencies.  |

### Outputs

| Type                                                               |
| ------------------------------------------------------------------ |
| [Modal Result](../../../../block-documentation/types/modal-result) |

***

<h2 id="fe-model-restraints-integer-scalar-scalar-120">
  FE Model, Restraints, Integer, Scalar, Scalar, 1.2.0
</h2>

Calculate the natural frequencies and mode shapes of an FE Model subject to prescribed boundary conditions. This block calculates a specified number of vibration modes. Providing minimum and maximum frequencies bounds the range of frequencies to be returned. Removing the optional Restraints input leads to a free-free Modal Analysis.

### Inputs

| Name            | Type                                                                                | Description                           |
| --------------- | ----------------------------------------------------------------------------------- | ------------------------------------- |
| Model           | [FE Model](../../../../block-documentation/types/fe-model)                          | The finite element model.             |
| Restraints      | [Boundary Condition List](../../../../block-documentation/types/boundary-condition) | The displacement restraints.          |
| Number of modes | [Integer](../../../../block-documentation/types/integer)                            | Maximum number of modes to calculate. |
| Min frequency   | [Scalar](../../../../block-documentation/types/scalar)                              | Lower bound of returned frequencies.  |
| Max frequency   | [Scalar](../../../../block-documentation/types/scalar)                              | Upper bound of returned frequencies.  |

### Outputs

| Type                                                               |
| ------------------------------------------------------------------ |
| [Modal Result](../../../../block-documentation/types/modal-result) |

***

<h2 id="fe-model-restraints-integer-scalar-scalar-130">
  FE Model, Restraints, Integer, Scalar, Scalar, 1.3.0
</h2>

Calculate the natural frequencies and mode shapes of an FE Model subject to prescribed boundary conditions. This block calculates a specified number of vibration modes. Providing minimum and maximum frequencies bounds the range of frequencies to be returned. Removing the optional Restraints input leads to a free-free Modal Analysis.

### Inputs

| Name            | Type                                                                                | Description                           |
| --------------- | ----------------------------------------------------------------------------------- | ------------------------------------- |
| Model           | [FE Model](../../../../block-documentation/types/fe-model)                          | The finite element model.             |
| Restraints      | [Boundary Condition List](../../../../block-documentation/types/boundary-condition) | The displacement restraints.          |
| Number of modes | [Integer](../../../../block-documentation/types/integer)                            | Maximum number of modes to calculate. |
| Min frequency   | [Scalar](../../../../block-documentation/types/scalar)                              | Lower bound of returned frequencies.  |
| Max frequency   | [Scalar](../../../../block-documentation/types/scalar)                              | Upper bound of returned frequencies.  |

### Outputs

| Type                                                               |
| ------------------------------------------------------------------ |
| [Modal Result](../../../../block-documentation/types/modal-result) |