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Stress analysis: Connecting rod

Note

The content of this tutorial is not up to date with the current live version of SimScale. The tutorial setup and the results are still valid! Please do not get confused if styles like buttons and entity names have changed in the meantime.

In this tutorial we will conduct a structural analysis of a connecting rod. Doing this, we like to show you how to set up a simulation run and produce results in a very short period of time.

Stress field of the connecting rod under pressure load.

Stress field of the connecting rod under pressure load.

Import tutorial project into workspace

Step-by-step

1) Getting started

  • To start this tutorial, you have to import the tutorial project “Tutorial-01: Connecting rod stress analysis” into your ‘Dashboard’ via the link above.
  • Alternatively, you can add the tutorial project from the ‘Public Projects’ library by searching for ‘tutorial’.
Search on community

‘tutorial’ search on community

  • Clicking on the project, then clicking on ‘Actions’ and ‘make a copy’ option to add it to your ‘Dashboard’. This process is illustrated by the figures below.
Make a copy through Actions

Making a copy of project to add it to Dashboard

  • Once the project is in your ‘Dashboard’, simply move the mouse over to the upper right corner click on the blue icon to open it in your workbench as shown in figure below.
Opening project from dashboard to workbench

Opening project from dashboard to workbench

2) Mesh Generation

  • Once the ‘Work bench’ is open you will be in the ‘Mesh creator’ tab.
  • Click on the CAD model CAD-connecting-rod_v1 to load the CAD model in the viewer
The CAD model displayed in the web browser

The CAD model displayed in the web browser

  • To create a new mesh from this CAD model, click the blue Mesh geometry button
  • Automatically, a new mesh called CAD-connecting-rod_v1 mesh is created and a default mesh operation called Operation 1 (you may rename it to a useful name)
  • To specify how exactly the mesh shall be generated, click on the operation itself i.e. Operation 1
  • First we need to choose the meshing type which basically defines the algorithm that will be used to create the mesh
  • For this static stress analysis, we will use the Fully automatic tetrahedralization mesh operation
  • It only has a few settings to choose: We set Mesh order to First order, the Fineness to 2 - Coarse and Number of processors to 2
Choose the type of mesh operation and its settings

Choose the type of mesh operation and its settings

  • That’s all for the mesh operation. Let’s start it by clicking the Start button on the top of the page
  • Confirm the dialog to start the operation
Confirm that you want to start this mesh operation

Confirm that you want to start this mesh operation

  • The Job Status box in the lower left will show the progress of the operation
  • Queued means that the SimScale platform is preparing a computer to carry out the operation
  • Computing means that the mesh operation is currently carried out
  • After the first seconds of computing, there will appear a Meshing Log tree item below our mesh operation in the tree
  • This is the direct command line output of the meshing framework, that in the beginning might be a bit cryptic but can be very useful if a meshing operation fails
The meshing log providing details of the mesh operation execution.

The meshing log providing details of the mesh operation execution.

  • Once the mesh operation is finished, the Job status box will show the green Finished box
  • The mesh immediately appears in the viewer and we can see the small elements that have been created
  • The advantage of running the mesh operation remotely is that you do not have to wait until the mesh is finished. You can simply move on and already work on the simulation setup since your local computer is not used at all for computing
The completed, tetrahedral, first order mesh.

The completed, tetrahedral, first order mesh.

  • This was all it takes to create an automatic, tetrahedral mesh on SimScale. You can also see the created elements of the mesh from inside at some cutout. To do so, apply a Mesh Clip filter by clicking on the Filter dropdown menu on top right and selecting Mesh Clip.
  • Next you will see a cutting plane which you can adjust under Mesh Clip parameters. For example, in this case give Normal (y) a value of -1 in order to clip the mesh from the middle of the geometry. Click Preview button to see the cutting plane. The black arrow shows the direction of clipping. Figure below elaborate the steps.
Mesh clipping

Mesh Clip filter

  • Click the Apply button to see the clipped mesh. Figure below shows the clipped mesh.
Clipped mesh

Clipped mesh

  • To get back to the standard mesh view, choose Filter and click on Clear Filter
  • Now let’s move on to the actual simulation setup.

3) Simulation Setup

Now after we have created the mesh, let’s define the actual simulation.

  • First switch to the Simulation Designer tab next to the Mesh Creator tab
  • Click on New Simulation
  • Give it a meaningful name
Give the simulation a meaningful name.

Give the simulation a meaningful name.

  • The first thing to do in any simulation setup on SimScale is to choose the actual analysis type that we want to carry out.
  • In our case, we are interested in running a static stress analysis, so we choose Solid mechanics and then Static
Choose the analysis type for your simulation.

Choose the analysis type for your simulation.

  • To confirm this analysis type, hit the blue Save button
  • Immediately the analysis template is loaded and the tree on the left is expanded
  • We can see different icons, that indicate different tasks
  • The red circle indicates that this item is missing something - a definition, or a choice
  • The green check means that this item is already completed - however you might want to check on the default values since they might not be suitable for your simulation
  • The blue circle indicates an optional settings that does not need to be filled out
  • Now we simply work our way from top to bottom of the simulation tree to complete the simulation setup
The simulation designer tree with all items necessary to complete the simulation setup.

The simulation designer tree with all items necessary to complete the simulation setup.

  • The first item is the Domain which defines the actual model or mesh on which you want to run this simulation
  • We choose the mesh connecting-rod-v1-mesh we just created and hit the blue Save button
  • Immediately, the chosen mesh is loaded in the viewer
The mesh that has been assigned to our simulation.

The mesh that has been assigned to our simulation.

  • The Domain tree item is then expanded with the items Geometry Primitives, Topological Entity Sets, Contacts and Mesh
  • However in this tutorial we won’t need any of them, so we simply go on to the next tree item
  • Under Model we don’t change anything and move on
The global model properties, that we leave as they are.

The global model properties, that we leave as they are.

  • The next relevant tree item is Materials where we click on the blue Add Material button to add a new material
  • The standard material Steel and its properties is added
  • We leave all detailed settings of the material model as they are
  • The only thing we need to take care of to complete the material definition is to assign this material to the volume of the conneting rod
  • This is done via the Topological Mapping table, where the only volume called volumeOnGeoVolumes_0 is visible
  • Simply marking the checkbox assigns the material to this volume which finishs the Material definition
  • Don’t forget to save - and the material icon in the tree with get the green check mark
Steel as material defined and assigned to the existing volume.

Steel as material defined and assigned to the existing volume.

  • The next tree item Boundary conditions is the place where we can define constraints as well as loads acting on the connecting rod.
  • For our simulation, we’ll only assign two boundary conditions: A pressure load at the lower end and a fixed support at the top end of the connecting rod.
  • Depending on the analysis type we chose, there would be even more boundary conditions available
  • We will start with the force boundary condition
  • So we click on the blue button Add Load boundary condition
The boundary condition dialogue.

The boundary condition dialogue.

  • Automatically, a new boundary condition called ‘boundary condition 1’ is created
  • First we’ll give it the meaningful name pressure-load which indicates the type of load
  • Next we’ll choose the type Pressure since we don’t want to deal with any directions - simply a normal pressure load is sufficient for this tutorial
Pressure load boundary condition.

Pressure load boundary condition.

  • Next we actually define the value. We chose 20e6 Pa which is around 20 bar
  • To complete the boundary condition setup, we have to choose on which faces this boundary condition shall be assigned to
  • So we select the two of the inner faces at the lower end of the connecting rod
  • Next we click on the blue button Add selection from viewer
  • This completes the pressure boundary condition which is indicated by the green check in the tree item of the boundary condition
Pressure load boundary condition completely defined.

Pressure load boundary condition completely defined.

  • The setup for a boundary condition is always the same: Give it a name, choose a type, choose the values and then assign it to a face set
  • So the second boundary condition we will define a fixed constraint at the top of the connecting rod
  • We add a displacement boundary condition, give it a meaninful name (e.g. fixed-constraint), choose Fixed value as the type and prescribe all displacement values to zero, which indicates that these faces are not allowed to move
The fixed constraint at the top of the connecting rod.

The fixed constraint at the top of the connecting rod.

  • The tree item Numerics allows us the control the solving mechanism in detail, where we also won’t change anything in this tutorial
  • The next important tree item is Simulation Control which allows to steer the overall simulation settings - however in our case, we will leave everything as it is
Settings for the simulation control tree item.

Settings for the simulation control tree item.

  • The last step to start this simulation is to create a Simulation Run from it, which basically means that we generate a snapshot of all simulation settings that will be saved and available for later review
  • So we switch to the Simulation Run tree item, and first check the simulation via Check simulation which should be successful, if we haven’t made any mistakes
  • Next, we hit the blue Create new run button and give the run a meaningful name for later review
  • And to start the run, we hit the Start button which will automatically find a machine for the simulation and carry it out
  • The Job status box in the lower left again provides updates about the job status like we saw in the meshing operation
The new run which is ready to be started.

The new run which is ready to be started.

  • Also as we saw in the mesh operation setup, a Solver log is provided after a few seconds which shows the exact output of the actual solver run
  • The simulation run should take a few minutes to be carried out
The completed simulation run.

The completed simulation run.

  • Once the simulation run is Finished we can move on to the Post-processor tab to visualize the simulation results

4) Post-Processing

  • Next we will visualize the results of the simulation we just completed, so we switch to the tab Post-Processor next to the tab we just worked in Simulation Designer
  • We click on the Solution fields tree item on the left under the name of the run we just ran (in our case, it is called 20-bar-load-case to indicate which thermal loads we have assigned)
  • Immediately after the click, the post-processing environment is loaded with a non-colored view of the results
The initial view of the post-processing environment without a any chosen color-coding.

The initial view of the post-processing environment without any chosen color-coding.

  • First, we want to see the von Mises stress field so we click on the Select field dropdown-menu on top of the post-processing window and choose vonMises_stress
  • Immediately, the von Mises stress field solution field is loaded as a color-coding of the result
The von Mises stress field color map.

The von Mises stress field color map.

  • To toggle the quantitative scale of the color map, we click on the red-crossed button next to the 20-bar-load-case text in the post-processing viewer
  • The color scale appears showing which region in our geometry has how much von Mises stress in MPa
The scale indicating the mapping between von Mises stress values (in MPa) and the colors.

The scale indicating the mapping between von Mises stress values (in MPa) and the colors.

  • Lastly we can also visualize other physical quantities of the results, for example the displacement field across the rod by again switching the field on top of the viewer
Displacement result field color coding.

Displacement result field color coding.

  • We can use further post-processing filters to generate a warped visualization of the connecting rod according to the computed displacement field
  • A click on the Add Filter button provides a list of all available filters
List of available post-processing filters.

List of available post-processing filters.

  • We choose the Warp by vector filter which allows to warp the results by the displacement field
  • The ScaleFactor in the warp by vector filter settings allows to exaggerate the displacement to get an understanding of the displacement field
Warped visualization next to the original results.

Warped visualization next to the original results.

  • Congratulations! You just completed a complete static stress simulation using the SimScale!