So, you’re designing a part that will support a rotary machine or an engine mount and you are done with your static analysis but wait! Have you done a Frequency Analysis?
Every structure has the tendency to vibrate at certain frequencies, be it natural or resonant frequencies. Each natural frequency is associated with a certain shape, called mode shape in which the model tends to assume when vibrating at that frequency. A frequency analysis calculates resonant frequencies and their associated modes of vibration.
Note: It is important to understand that resonant frequencies and associated modes of vibrations are the only things calculated by a frequency analysis. A frequency analysis does not calculate displacements or stresses.
With SOLIDWORKS Simulation Professional, you can create a Frequency Study and evaluate the model, the natural vibration modes of your design and compare them to the frequency generated by the machine or equipment in use.
The frequency study settings are easy and straightforward, as always, the case with SOLIDWORKS. We’ll go through the step-by-step process in a sample case study below.
In this case study, we will determine natural frequencies and corresponding mode shape of a tuning fork and see if the fundamental frequency is indeed 440Hz. Some key stages in the analysis of this part are shown in the following list:
Right click the study and select properties, under options enter 4 for Number of frequencies, so that the first four natural frequencies are calculated.
Select and assign material, Chrome Stainless Steel, to the parts
Apply a Fixed Geometry fixture to the face of the ball at the end of the stem as shown
Mesh the model with high quality elements and default Maximum element size of 1.475mm. Use Curvature mesh.
Under the results folder you will see there are four amplitudes of mode shapes plot.
The fundamental frequency 440HZ is actually the fourth mode.
Right click the results folder and select List Resonant Frequencies
Now based on this result it is easy to make the decision whether or not this design fits its purpose.