SIMSCAPE MULTIBBODY CANTILEVER BEAM MODEL

I CREATED A CANTILEVER BEAM SIMULATION IN SIMSCAPE MULTIBODY . IN THE SCOPE OF ACCELARATION AND TRANSLATION USING TRANSFORM SENSOR WHEN THE EXTERNAL FORCE ACTS IN Y DIRECTION AS ACHIRP SIGNAL. I AM NOT GETTING ANY PEAKS BECAUSE OF RESONANCE WHICH CLEARLY SHOWS IT VARIES LARGELY FROM PHYSICAL MODEL DATA.. HOW CAN I GET THE RESONANCE AND NATURAL FREQUENCY BEHAVIOUR IN THE BEAM OUTPUT DATA

Answer 1

[Kothuri]

Hi Usha,

I understand that you are simulating a Cantilever beam using Simscape Multibody and are trying to get the resonant and the natural frequency in the beam.

You can try the following steps:

• Ensure that the output data of the beam(acceleration, displacement etc.,) is accurate and the peak points in the data represent the resonant points.
• Convert the time-domain data to frequency domain using Fast Fourier Transform(FFT) as it will indicate the dominant frequencies present in the data.

You can refer the below links for more info on FFT

https://www.mathworks.com/help/dsp/ref/fft.html

https://www.mathworks.com/help/matlab/ref/fft.html

• Resonance occurs when the external force(chirp signal) frequency matches the natural frequency of the system.
• From the frequency spectrum, identify the peak frequency corresponding to resonance and calculate the natural frequency of the cantilever beam.
• The natural frequency of the cantilever beam can be calculated using the formula: NaturalFrequency = frequency(1)/(2*pi)

In this way you can calculate the resonant and natural frequency of the cantilever beam.

You can refer the below link for more info on the frequency calculation of the cantilever beam.

https://www.mathworks.com/help/pde/ug/dynamics-of-a-damped-cantilever-beam.html#cantileverBeamDampedTransient-1