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HimanshuM2376
What is the condition for resonance to occur in case of underdamped forced vibrations?
Can you please elaborate?anorlunda said:lack of negative feedback
HimanshuM2376 said:Can you please elaborate?
Thanks. What I want to know is that for an underdamped system undergoing forced vibration the maximum amplitude occurs when the excitation frequency is less than natural frequency when we increase the value of damping ratio.SCP said:Resonance occurs when the input to a system occurs at a frequency that matches a natural frequency of the system. When this happens, the input continuously adds energy to the system, so oscillations get continuously larger. In a simplified mathematical model of an undamped system, the amplitude of the system output will go to infinity during resonance. In the real world, either system failure (for example a broken spring in a mechanical system), non-linearities (such as the spring stiffness changing as it flexes), or the presence of damping (such as friction in mechanical systems) will limit the resonant amplitude to some finite value.
I believe this is equivalent to the electrical analogy of a parallel resonant circuit. Resonance is sometimes defined as the frequency when current and voltage are in-phase. But for the heavily damped parallel circuit, this frequency does not coincide with maximum amplitude.HimanshuM2376 said:Thanks. What I want to know is that for an underdamped system undergoing forced vibration the maximum amplitude occurs when the excitation frequency is less than natural frequency when we increase the value of damping ratio.
Resonance in underdamped forced vibrations refers to the phenomenon where a system oscillates with a large amplitude at a specific frequency when subjected to a periodic external force. This frequency is known as the resonant frequency and is dependent on the system's natural frequency and damping coefficient.
Resonance occurs in underdamped forced vibrations when the frequency of the external force matches the system's natural frequency. This causes the amplitude of the system's vibrations to increase significantly, as the energy from the external force is absorbed and added to the system's own energy.
The effects of resonance in underdamped forced vibrations can be both beneficial and detrimental. On one hand, it can be used to amplify signals in electronic circuits or musical instruments. On the other hand, it can lead to structural damage or failure in buildings and bridges due to excessive vibrations.
To prevent resonance in underdamped forced vibrations, the system's natural frequency can be adjusted to be different from the frequency of the external force. This can be achieved by changing the system's mass or stiffness, or by adding damping elements to dissipate energy and reduce the system's amplitude of vibration.
Resonance in underdamped forced vibrations can be observed in various everyday objects and phenomena. Some examples include a child swinging on a swing with proper timing, a singer breaking a glass with a high-pitched note, and a bridge collapsing due to wind-induced vibrations at its resonant frequency.