> ## 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 use Ramps to create varying fields for FEA Materials and Boundary Conditions

## Objective:

Learn how to use ramps and implicit bodies to define a field of engineering data that can be used as inputs into a simulation analysis.

## Procedure:

#### **Constant Field:**

Traditionally, material properties are defined with constant values. nTop defines scalar engineering values as Scalar Fields. In the figure below, you can see that the Thermal Conductivity is set at 152 W/(m\*K) and results in a field that does not change.

**![An example Isotropic Material that has a constant field value. The field is defined by the constant Conductivity value.](https://files.learn.ntop.com/help-articles/structures/1500000023142.png)**

#### **Transforming Distance Fields to Engineering Scalar Fields using the Ramp Block:**

The [Ramp Block](https://support.ntopology.com/hc/en-us/articles/360041676813-Introduction-to-the-Ramp-Block) allows you to use an input field to spatially transform field data into engineering units. This functionality bridges the divide between field and engineering data and allows complex analysis.

<Card>
  <table>
    <tbody>
      <tr>
        <td>
          <figure>
            <img alt="ramp.jpg" src="https://files.learn.ntop.com/help-articles/structures/48745678830995.png" />
          </figure>
        </td>

        <td>
          <img alt="The icon for spatially varying fields. " src="https://files.learn.ntop.com/help-articles/structures/1500000037981.png" />
        </td>
      </tr>
    </tbody>
  </table>
</Card>

Using this functionality, you can now see that the Thermal Conductivity varies from 152-200 W/(m\*K) at a distance from 0-100 mm from the Axis Location.

![Instead of a constant conductivity value, this isotropic material has a varying conductivity value. This is created by applying the ramp block and defining how the conductivity will change from the center of the body moving outward.](https://files.learn.ntop.com/help-articles/structures/360101112513.png)

#### **Varying Field using Multiple Objects:**

Similarly, you can use multiple implicit bodies with the ramp block to produce more complex field patterns. In this case, an array of cylinders are used.

![The image shows how to use bodies to manipulate a field.](https://files.learn.ntop.com/help-articles/structures/360101114513.png)

#### **Boundary Conditions:**

Just like material properties, certain FEA boundary conditions can vary using scalar field inputs. Examples of these types are shown below.

<Card>
  <table><tbody> <tr> <td> <strong>Structural Boundary Conditions</strong><br /><strong>with Field Inputs </strong> </td> <td> <strong>Thermal Boundary Conditions </strong><br /><strong>with Field Inputs</strong> </td> </tr> <tr> <td>  <img alt="The Edge Force, Surface Force, Acceleration Load, and Pressure blocks." src="https://files.learn.ntop.com/help-articles/structures/1500000068302.png" /></td> <td>  <img alt="The Surface Heat Flux, Convection Boundary Load, Radiation Boundary Load, Volumetric Heat Generation, Heat Generation, Temperature Restraint, Initial Temperature, and Applied Temperature blocks." src="https://files.learn.ntop.com/help-articles/structures/1500000068322.png" /></td> </tr> </tbody></table>
</Card>

In this instance, convection coefficients can easily be varied using the Ramp block, in the same manner, shown for spatially varying material properties.
![A lattice structure that has a varying convection coefficient field applied to it. The field contains smaller values at the center and gradually increases as it spreads towards the edges of the lattice.](https://files.learn.ntop.com/help-articles/structures/1500000066821.png)

And that's it! You've successfully defined varying structural and thermal material properties using fields.

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/Ramps%20to%20Create%20Varying%20FIelds%20for%20FEA%20Example.ntop)

## Keywords:

*FE analysis simulation FEA vary Fields Elastic Modulus Conductivity Material Properties Implicit Bodies Ramp spatially Field*