Terminologies

1. Introduction

In this tutorial, we will walk through the process of simulating a beam frame using 1D beam elements. With the help of Akselos Modeler, you will learn how to create the beam frame model, apply loads, define boundary conditions, and run the simulation. This step-by-step guide will provide a clear workflow for setting up and solving the model. 

 Figure 1.1. The 1D beam frame analysis workflow

In this tutorial, we use the 1D beam element to simulate the beam frame model which is constrained at 4 legs, under forces applied on 4 points on top. The model schematic and beam cross-section are shown in the figure below. 

 Figure 2.1. The beam frame problem

The beam geometry, beam properties, and load cases used in this example model are as follows:

• Beam cross-section (m): Tubular with  below dimensions:
  • Diameter: 2 (m)
  • Thickness: 0.06 (m)
• Material: Elasticity with the below properties:
  • Mass density: 8000 kg/m³
  • Poisson ratio: 0.3
  • Young Modulus: 210 GPa
• Applied loads:
  • Self-weight
  • Point load: F_V= F_H = 30 MN

Figure 2.2. The beam Cross-section

• A new collection in your Organization is required to store this model on Akselos Portal (https://dashboard.akselos.com). Don’t know how? Read more Start building your asset with a new collection.
• Akselos Modeler – our simulation is required to build this model.
• A sample collection has been prepared for you to use as a reference. Find the 1D_Beam_Frame here on Akselos Portal.
• By default, you can use Akselos Cloud (available in Akselos Modeler).

Note:
▶ If you have not installed Akselos Modeler yet, please see Akselos Modeler 2023 - Installing, Updating and Managing the Akselos Simulation Software to download and install the software.
▶ If you have trouble accessing to any of those pre-requisites. Please contact us at: support.akselos.com

Follow the steps below to import the 1D_Beam_Frame collection into Akselos Modeler:

• In Akselos Modeler, click on the Cloud tab on Ribbons → Authentication → Enter your username and (password or token) → Click on the Check button and wait for Authentication status to turn green and show Authentication successful. 

Figure 3.1. Checking authentication

• On the Collections tab, click on Import Collection… → On the Import Collection window, find and select 1D_Beam_Frame collection → Click on the Import button to pull the collection into your computer. You will receive a success message on the Logs screen when the collection is successfully imported.

Figure 3.2. Importing 1D_Beam_Frame collection into the local machine

• On the File tab, click on New Model from Current Collection. The collection is ready to use after this step. 

Figure 3.3. Create a new working space in the 1D_Beam_Frame collection

4. Implementation

This section outlines the step-by-step process to create, set up, and solve a beam frame model in Akselos Modeler. The workflow includes defining the geometry, assigning materials and cross-sections, applying constraints and loads, running the solver. 

 Figure 4.1. The 1D beam frame analysis workflow

Step 1: Create Nodes

Figure 4.2. Create Model – Create Nodes

Akselos Modeler provides an Edit Beams tool that helps users create nodes and beams. The tool also can modify beams such as split/merge or change the beam type.

• On the left panel, select the Edit Beam tool.

Figure 4.3. The Edit Beams tool interface

To build the beam frame, 13 nodes need to be created first. Akselos Modeler provides tools for manually creating nodes or quickly importing multiple nodes using a CSV file with coordinates. For this tutorial, we have prepared a CSV file available in the collection - Model_Node.csv.

Figure 4.4. Creating nodes manually

• Option 2 - Creating nodes from csv file: Click the Import icon shown below, select Model_Node.csv in the collection to import the file. The node coordinates will appear in the table, just like in Option 1. Finally, click the Create Nodes button to generate the nodes. 

Figure 4.5. Creating nodes from the csv file

Once the above steps are completed, 13 nodes will appear in the Graphic Window. 

Figure 4.6. Thirteen nodes on the Graphic Window after creating

Step 2: Create Beams Model From Nodes

Figure 4.7. Create Model – Create Beams Model From Nodes

From these nodes, you can create the beam frame. Click the Create Beam From Nodes button, then select nodes in the Graphic Window — each pair of selected nodes will form one beam. Repeat this process until all 28 beams are created, completing the model 

Figure 4.8. Creating beams from nodes

Step 3: Split Beams

Figure 4.9. Create Model – Split Beams

Note: You can skip this step but to increase the accuracy of the result, splitting the beam into multiple elements is also important.

Figure 4.10. Splitting beams

Figure 4.11. The model after splitting

In this step, we will guide you to create and define a cross-section and then apply it to the model.

• In the Model Tree on the left panel, right-click on Model → Insert Property → Cross-Sections. The group of cross-sections will be created with one default item. You can add more Cross-sections by right-clicking on the group →Insert Property → Crosssectiongroupitem or delete them by clicking on then pressing the Delete button.

Figure 4.13. Creating CrossSectionGroup

• Click on Cross-Section 1 then see the Property Tree → Define the dimensions.

Figure 4.14. Defining Cross-section properties

After this step, the cross-section has been created but is not yet assigned to the beams. We will proceed to Step 5, and once it is completed, the software will automatically assign both the cross-section and material to the beams. At that point, we will review where to modify them if needed.

In this step, we will guide you to create and define a material and then apply it to the model.

• In the Model Tree on the left panel, right-click on Model → Add Property → Materials. The group of materials will be created with one default item. You can add more items by right-clicking on the group → Insert Property → Materialgroupitem or delete them by clicking on then pressing the Delete button.

Figure 4.16. Creating MaterialGroup

• Click on Material 1 then see the Property Tree → Define the parameters for material.

Figure 4.17. Defining material properties

As mentioned at the end of Step 4, once the material is created, the software will automatically assign both the material and cross-section to the beam. To verify this, switch to Mesh Elements Selection mode, select any element (To quickly select multiple elements, click and drag to create a selection box) on the Graphic Window, and expand the Properties section in the Property Tree. There, you will see the assigned items for that element.

Figure 4.18. A place to check material/cross-section items that are assigned to the beam 

Akselos Modeler provides a tool to visualize the beam's cross-section. In the Graphic Window, open the Configure View Settings menu and enable the Show Beam Cross-section option 

Figure 4.19. Showing beam model with cross-section on the Graphic Window

In this tutorial, four legs of the frame are constrained. We will constrain 4 nodes at the bottom of the model. Before doing it, we need to create a Node Port at these nodes and then fix them.

• Firstly, we need to turn on the Unconnected Ports and  Boundary Conditions options in Configure view settings. The ports and boundaries of the model are visualized on the Graphic Window.

Figure 4.21. Turning on Unconnected Ports and Boundary Conditions options

• Box-select the four bottom nodes as shown in the figure below. Right-click on the Graphic Window → Filter Selection → Choose NodeGeomType to keep only nodes. Once only nodes are selected, right-click again → Create Node Port. 

Figure 4.22. Creating Node Ports

Figure 4.23. Four node ports are created

• To constrain them, select the four newly created node ports, then go to the Property Tree and choose (x, y, z, theta_x, theta_y, theta_z) under Constraint Type. The software will automatically apply the same constraints to all selected ports. Once completed, black points will appear at the four ports, indicating they have been successfully constrained. 

Figure 4.24. Constraining node ports

Figure 4.25. The model with four constrained nodes

In this tutorial, there are two load cases applied to the mode (Self-Weight & Point-Load). Self-Weight is applied on a subdomain selection and Point-Load is applied on four nodes. To create a load applying on the node, we need to create a Node Set and store them in Stored Selection.

• Create Node Set:
  • Change to the Collection ribbon → Show component tree → Right-click on Boundary Sets → Create Boundary Set → Node.

Figure 4.27. Creating Node Set

Figure 4.28. Selecting four nodes for Node Set

Figure 4.29. Turning on the PointLoad operator

Figure 4.30. Saving component

• Stored Selection for Self-Weight Load Case:
  • Change to the Model ribbon → On the left panel, right-click on Stored Selections → Create Subdomains Selection.

Figure 4.31. Creating Subdomains Selection

Figure 4.32. Storing Subdomain for Self-Weight load case

 Figure 4.42. The load vectors of the point load appeared after applying

To easily manage the load case, we should rename them following the load (Right-click on it → Rename this Load Case or click on it → press F2). Load Case 1 is Self-Weight & Load Case 2 is Point-Load.

Figure 4.43. Renaming the load cases

For the 1D beam element problem, we can only solve it with the FEA solver.

• Under Solver Options on the left panel, there is RB-FEA Options, it is the default and can be used with some changes. Click on RB-FEA Options → See the Property Tree and change Solver Strategy to FEA. After changing, the name of the default solver will automatically change to FEA Options.

Figure 4.45. The default Solver Option

Figure 4.46. Setting FEA Solver

• In the Property Tree of FEA Options, you can choose the result fields that you want to visualize. The default results of the solution are displacement in x, y, z - directions. In this example, we choose some additional fields which are Axial Force, Shear Forces and Bending Moments. Turning on two options as in the figure below.

Figure 4.47. Adding some fields in the Solver Option

• Set Scenario: Under Scenario on the left panel, there is Default Scenario and we use it. Click on Default Scenario → See the Property Tree and set the coefficients of Point-Load and Self-Weight to 1.0.

Figure 4.49. Setting Scenario

• Set Solve List: Since there is only one scenario, select the default in Solve List to check that the default scenario is turned on.

Figure 4.50. Setting Solve list

Now we can proceed to solve the model. Firstly, we have to save the aks file to save all setting up the model → Sync the collection to Akselos Dashboard → Run solving.

• Save aks File:
  • Click on the File tab → Save.

Figure 4.52. Saving aks file

Figure 4.53. Naming and saving aks file

• Sync Collection:
  • Click on the Collections tab →Sync with Dashboard.

Figure 4.54. Syncing collection

Figure 4.55. Committing for synchronization

• Run Solving:
  • Change to the Solutions ribbon → Click on the Solve button. The solving request will be submitted to Akselos Cloud. You will see the status of this request on the Solution tree. You can see the results once the solving is done, which is usually within seconds with Akselos solver. 

Figure 4.56. Solving model

Figure 4.57. The solution

There are some solution fields (visualization & results). You can review it to compare it with yours.

Figure 5.2. Axial Force result

Figure 5.3. Displacement x-direction result

Figure 5.4. Displacement y-direction result

Figure 5.5. Displacement z-direction result

Figure 5.6. Bending Moment results

Figure 5.7. Shear Force results

Related Articles & Similar Case Studies:

• Before we start - Overview of Akselos simulation procedure
• Cantilever Beam with 1D Elements
• Cantilever Beam with 2D Shell Elements
• Cantilever Beam with Solid Elements