Hello All,
As we plot a frequency response curve for a forced vibrating system after applying the perturbation method (MMS). I would like to ask whether the ampliutude at any frequency (as represented in frequency response curve) is exaclty the same as that which will be obtained by integrating the equation of motion? Or is it just a representation of how the amplitude of the motion will vary as the forcing frequency will cross/move aorund the natural frequancy?
I'am attaching a represntative frequancy response curve for your ready reference.
Hello Pravesh,
In the plot you are presenting you should check what the variable "a" in your y-axis is. Sometimes, when applying a perturbation method for nonlinear mechanical systems (for example a Duffing oscillator), the equations are solved in barycentric coordinates and your variables would no longer be your initial physical variables. I would check if this is the case (please notice that you will still be able to go back to your physical variables if this is the case). Another point you should double check is whether in the graph the output has been normalized by the input.
Hope this helps.
Best,
G.
Hello Parvesh,
The amplitude in frequency response function that you have plotted should be same with what you get from equation of the motion. Basically, they are the same things but you might get some numerical error while applying the perturbation method. Also, check with the damping value by changing in the EOM and observing it's effect on the displacement response.
Best,
Amir
Thanks to all,
Yes the amplitude represented by frequency response curve is same as that shall be obtained from numerical integration of equation of motion.
- Badges
- Science method