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serbring
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I have estimated some transfer frequency functions of complex mechanical suspension. It is shown the gains reach a very high value at a 0.8Hz. How could i know if the 0.8Hz isthe suspension natural frequency?
Cyrus said:This question does not even make sense, do you know what a natural frequency is? Also, what is a transfer frequency functions? Do you mean you have a transfer function, obtained analytically via frequency sweeps?
Side:
Please capitalize the word "I" in sentences.
serbring said:I have estimated some transfer frequency functions of complex mechanical suspension. It is shown the gains reach a very high value at a 0.8Hz. How could i know if the 0.8Hz isthe suspension natural frequency?
berkeman said:It does sound like it is a resonant frequency, if you are getting amplitude gain there. Is it the only resonant frequency you have found in your sweep? You should be able to start to calculate the resonant frequency based on the spring constant and the unsprung mass, I would think.
Cyrus said:Resonance occurs when the bode magnitude plot reaches a peak.
serbring said:Is it always true? Moreover does resonance occur when the bode phase plot reaches 90°?
serbring said:Is it always true? Moreover does resonance occur when the bode phase plot reaches 90°?
Mike_In_Plano said:When I don't know the values in my system (ie mass compliance, damping), I often modify a known value (ie mass) and observe the effect. For a second order system, it's easy to ascertain the baseline mass based upon the added mass and frequency shift.
Then, knowing the baseline mass and the baseline resonance, you can compute the compliance.
Of course it gets much more tricky if you're coupled into another system...
berkeman said:Why would you say 90 degrees?
Mike_In_Plano said:When I don't know the values in my system (ie mass compliance, damping), I often modify a known value (ie mass) and observe the effect. For a second order system, it's easy to ascertain the baseline mass based upon the added mass and frequency shift.
Then, knowing the baseline mass and the baseline resonance, you can compute the compliance.
Of course it gets much more tricky if you're coupled into another system...
Natural frequency determination is the process of identifying and measuring the frequency at which an object or system naturally vibrates without any external force. It is a fundamental concept in the field of mechanics and is used to study the behavior of structures, machines, and other physical systems.
Understanding the natural frequency of a system allows scientists and engineers to design and build structures and machines that can withstand vibrations and avoid resonance, which can cause damage or failure. It also helps in predicting the behavior of a system under different conditions and making necessary adjustments to ensure safety and efficiency.
Natural frequency can be determined through experiments or mathematical calculations. In experiments, the system is excited with a known force, and the resulting vibrations are measured and analyzed to determine the natural frequency. In mathematical calculations, the properties of the system, such as mass, stiffness, and damping, are used to calculate the natural frequency.
Several factors can influence the natural frequency of a system, including its mass, stiffness, and damping. The shape and size of the system also play a role, as well as the material it is made from. External forces, such as wind or earthquakes, can also affect the natural frequency of a structure.
Yes, the natural frequency of a system can be changed by altering its properties, such as its mass, stiffness, or damping. For example, adding weight to a structure will decrease its natural frequency, while increasing its stiffness will increase the natural frequency. Additionally, applying external forces can also change the natural frequency temporarily.