> ## 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 create a Simulation Model for a simple shell lattice

## Objective:

Set up a simulation for a Shell Lattice with a solid body and learn how to use the Shell Attribute.

## Applies to:

* Cutting down meshing time
* Simulating Shell Lattices

## Procedure:

**1. Set up:** We start with an imported CAD Model:

* The CAD bodies have been converted to implicit bodies
* The volume lattice was generated using the inner implicit body region

**2.** **FE Mesh:** To simulate our geometry, we need two separate FE Meshes. One for the lattice and one for the solid border.

* Add an **FE Lattice Mesh** block and input the Interior Lattice.
* Set the Geometric Order to Linear and leave the Subdivisions as 1.

![The FE Lattice Mesh that is generated using the inner volume lattice.](https://files.learn.ntop.com/help-articles/structures/48214212837011.png)- - [Create an **FE Volume Mesh** for the outer border](/help-articles/knowledge-base/meshing-workflows/how-to-create-an-fe-volume-mesh).

**3.** **Simulation Domains:** The Simulation Model needs a Domain for every mesh.

* Create the Shell Domain: Add a **Solid Domain.**
* Input the **FE Lattice Mesh**from Step 2.
* Input a **Shell Attribute.**
  * Set the Thickness and Material.

![The Solid Domain and Shell attribute blocks that are used to define the lattice region.](https://files.learn.ntop.com/help-articles/structures/48214229441299.png)- - Create the Outer Solid Domain: Add a **Solid Domain.**

* Input the **Outer FE Mesh** from Step 2.
* Input a **Solid Attribute.**
  * Set the Material.

![The Solid Domain and Solid Attribute blocks that are used to define the outer region.](https://files.learn.ntop.com/help-articles/structures/48214229444883.png)

**4.** **Simulation Model - Tie Constraint:** Any Simulation Model with more than one domain needs a Tie Constraint to define how the domains are tied together.

* Add a **Tie Constraint** block in the Connector input.
* Add an **FE Boundary by Body** block to the Independent and Dependent Boundary inputs.
  * For the Independent Boundary, use the outside border. Use the [**FE Boundary by Body**](/help-articles/knowledge-base/structures/how-to-select-boundaries-using-boundary-by-body) block to select it.
  * For the Dependent Boundary, use the Shell Lattice. Use the **FE Boundary by Body** block to select where the Shell touches the Outer border.
* Set the Radius on the **Tie Constraint** to 1mm to allow for the Shell Lattice to be selected.

![The Simulation model containing the Shell and Outer Solid Domains. The Domains are connected using the Tie Constraint.](https://files.learn.ntop.com/help-articles/structures/48214212842131.png)The Shell Lattice is now all set up! After step 4, the steps to run the simulation are the same. All you need to do is add [**Boundary Conditions**](/help-articles/knowledge-base/structures/how-to-use-boundary-conditions) and [**run the simulation**](/help-articles/knowledge-base/structures/how-to-run-a-static-analysis). Read the articles linked above for more information on those steps.

Are you still having issues? Reach out to 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/Simulation%20Model%20for%20Shell%20Lattice%20Example.ntop)

## Keywords:

*analysis mesh simulation lattice volume shell fe constraint solid attribute tie simulate meshes*