Documentation

Tutorial: Connecting Rod Stress Analysis

Stress field of the connecting rod under pressure load.
Stress field of the connecting rod under pressure load.

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.

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.

The CAD model displayed in the web browser

Workbench
Workbench

2) Simulation Setup

  • Click on the “+” button to create a New Simulation.
  • In our case, we are interested in running a static stress analysis, so we choose Static.
CreateStaticSimulation
Create Static Simulation
  • To confirm this analysis type, hit the blue Ok button
  • Give an appropriate name to the Simulation. Example – Static-Stress-Analysis
Workbench
Workbench
  • 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 refers to the already completed item – however you might want to check on the default values since they might not be suitable for your simulation
  • Now we simply work our way from top to bottom of the simulation tree to complete the simulation setup
  • The first item is the Geometry which defines the actual model on which the Simulation is going to be performed
  • We choose the Geometry CAD-connecting-rod-v1 as our Domain
Geometry
Geometry
  • The next important thing on the workflow will be the Mesh
  • When the Mesh icon is clicked, SimScale autonomously chooses a “Tet-Dominant” Mesh required for a Static Analysis
  • For this tutorial, the default mesh settings are sufficient to get a good quality mesh
  • Click on the Generate Button to start the meshing operation
Meshing Operation
Meshing 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
Mesh Status
Mesh Status
  • 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.

  • 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
  • You can also see the created elements of the mesh as various section views. To do so, click the Mesh Clip filter
  • 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 Clip filter
Mesh Clip filter
  • Click the Generate Mesh Clip button to start mesh clip. Clipping might take few minutes depending upon the geometry to complete. Figure below shows the clipped mesh.
Clipped mesh
Clipped mesh
  • For this tutorial case, Element  technology and Model can be skipped
  • The next relevant tree item is Materials where we click on the “+” 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 solid_0 is visible or by just selecting the volume from the viewer itself
  • Don’t forget to save – and the material icon in the tree with get the green check mark
Material Selection
Material Selection
Material Assignment
Material Assignment
  • 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 “+” button to add a new Boundary condition
  • Automatically, a new boundary condition called ‘boundary condition 1’ is created
  • First we’ll give it the meaningful name Pressure-Load for our reference
  • Set the value for pressure as 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
  • 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
Pressure load boundary condition
  • 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
  • Similarly, a fixed constraint boundary condition is defined at the top of the connecting rod
  • To do this, a Fixed value boundary condition is selected and all displacement values are set to zero, which indicates that these faces are not allowed to move
Fixed constraint at the top of the connecting rod
Fixed constraint at the top of the connecting rod

 

  • The tree item Numerics allows us the control the solving mechanism in detail, where default values are left as such for this case
  • 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
Simulation Control
Simulation Control
  • The last step to start this simulation is to create a Simulation Run
  • Once all the settings are done correctly, click on the + button near the Simulation Runs to create a new run
  • To start the run, the Start button is clicked
  • The Job status box in the lower left again provides updates about the job status like in the meshing operation
Start Simulation
Start Simulation
  • 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 completed
Solver Log
Solver Log
  • 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
  • Click on the Post-process Results button to load the results on the viewer
Post-ProcessingResults
Post-Processing Results
  • For example, to check the von Mises stress on our model, click on the Results and then select the von Mises stress fron the Scalar list below.
von Mises Stress
von Mises Stress
  • The color scale corresponds to the distribution of von Mises stress in our model
  • 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 plot
Displacement plot
  • We can use further post-processing filters to generate a different visualization of the connecting rod according to the computed displacement field
  • A list of all the available filters can be seen on the left side.

 

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