Wednesday September 10, 2014 at 11:25am
This blog describes how to add a transient time step into a Simulation Design Study. This enables users to graph stress results across time steps to see worst case.
Many simulations require an understanding of not just one load case or transient time step, but many. Design Studies are invaluable for this and allow you to set up multiple loads and view the results in a neat table.
To many users, and certainly those who have attended the SOLIDWORKS Simulation training course, this is not news. The training example is a wishbone suspension system that experiences a range of loads and a variety of material thicknesses. Great - but what happens if the parameter to vary is not a load or a material or a dimension? For instance, let's use a brake rotor as an example.
We wish to determine the highest Von Mises stress due to thermal expansion. A transient Thermal study has been run with a short duration heat input - and we can view the transient thermal behaviour easily enough. However, if we want to see the transient stresses we need to run a Static study with a specific transient thermal time step. The time step is selected in the Properties of the Static study as shown below ....
This selects the 40th time step of the Thermal study called 'Transient - Heating' and uses the temperatures to calculate the thermal stresses.
However, there isn't a drop down to link this to a Design Study as there is with loads. So how exactly do you make the link between a parameter and the study Properties? The answer is quite simple if you read the text in the window - but often users don't (I am in that camp!).
With the Parameter window open, all you need to do is select the study name at the top of the relevant Simulation study tree. When you do so the Properties that can be linked to a Parameter are shown in the window (see image below) and the radio buttons can be ticked to switch them on. You can now select the 'Apply' button and you should see an asterisk in the right hand column of the table to indicate it has successfully linked.
Once linked to the Design Study, you can choose any or all of the transient time steps to vary. In the brake rotor example I picked all 40 time steps.
You can then run the Design study with a 'Monitor only' stress sensor. This can then be graphed to find out at what time step the stress maxes out. Below you can see the max stress is reached at time step 12 - which is after 1.5 seconds.
Here is the stress at that time step ...
The alternative method is to manually change the time step in the Static study properties and rerun - 40 times! Not a great way to spend the afternoon!
Once you know you can do this, you will find all sorts of uses for Design Studies - for instance mesh convergence.
by Andy Fulcher
Solid Solutions Management Ltd