Welcome back to our monthly review of your support questions! Let’s take a look at the most frequently asked questions in March 2021.
How is a FFT computed?
A FFT can be computed in Post Processor or Review. Resolution of the FFT is determined by the timestep of the model so will be linked directly to how fine the mesh is and what input function (frequency content) is driving the model. The mesh has to support the highest frequencies that you want to see in the simulation. The input signal also has to contain energy at these frequencies you want to evaluate in the simulation. If you want to increase FFT resolution you can zero pad the data to create more frequency bins in the calculation using the time pad command in Review. Or you can increase the padding in the Post Processor mode by going to Post Processor > Configurations (Gear Icon top right) > Post-Processor Settings.
How can I pattern out geometry?
Building patterned geometry such as arrays can be tedious task. However, OnScale supports patterning of geometry to speed up this process. You can pattern out geometry in both Analyst and Designer.
Analyst
In Analyst mode you can make use of keypoints to pattern out a geometry. The symb #keycopy command allows you to replicate keypoints by specifying a range of keypoints to copy in XYZ. This then allows you to copy out materials between these keypoints in the same manner using site regndupl. A good example of this method is our Analyst: 1-3 Piezocomposite Array.
Designer
In Designer mode primitive shapes can be patterned out in a linear fashion by specifying the number of repetitions and separation distance in XYZ.
However, note that all materials will also be copied out, not just the geometry. A good example of this method is our Designer: 1-3 Piezocomposite Array.
How do I parameterize inputs?
Inputs can be parameterized in Analyst and Designer.
Analyst
If a model is set up using keypoints the variables used in the symb #keypnt command are used to alter the geometry of the model. Also, any variable declared using symbx will appear in the Cloud Scheduler to allow you to sweep this variable in the cloud.
Designer
Model geometry can be parameterized in Designer using the Parameter Table.
To use one of these parameters for the dimensions of your model, click on the x next to the model property you wish to parameterize and select Use Parameter for Property.
You can then select from a drop-down menu which parameter to assign.
Note that if you wish to sweep any of these variables in the cloud you must select the Varying tick box for that parameter in the Parameter Table. See this article for more details.
CAD geometry can also be parameterized using Onshape. Here is a short demo video of this process.
