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Questions tagged [frequency-response]

54 questions
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Is a 3 Hz beat frequency from my neighbor's HVAC a sign of a malfunction?

I'm being annoyed by a pulsating hum which comes from my neighbor's HVAC system. I read up a little on the design of HVAC systems and I came to a tentative conclusion that what I'm hearing is a compressor being driven by an AC induction motor. A…
Metamorphic
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Elastic (Young's) Modulus relation to the Eigenfrequency

I would like to compare the shape of the frequency spectrum of a plastic and aluminium component. Now if we assume that the plastic and aluminium component only differ in the material, while the mass and stiffness stay the same (I know, large…
mcluka
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Generating a Blank Seismic Tripartite Graph

I am performing a calculation in which I need to plot a generated response spectrum to a seismic tripartite graph. However, I am having a heck of a time finding a blank tripartite graph online. A low-resolution example is shown below. How might I…
grfrazee
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How to determine the dynamic response of a spring-mass system?

The Problem I have the following system for which I would like to determine its dynamic response, taken from these lecture notes pg.20: where the forcing functions are $u_1 = 1-U(t - t_0)$, $u_2=0$, and $u_3=0$, $U(\cdot)$ is the unit step function…
kostas1335
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What is the frequncy range of seismic vibrations?

I'm working on a structure which needs to sustain common seismic vibrations due to earthquakes. So I want to do some modal analysis to find natural frequencies of the structure and make sure they are out of the range of seismic vibrations. I'm being…
Foad
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What type of test signal is appropriate for frequency response analysis of string instruments?

I want to test the frequency response of stringed musical instruments . My test set-up includes a piezo film transducer which is just taped onto the instrument and fed a signal which then vibrates the instrument. The resulting sound is picked up by…
William Hird
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Getting the damping ratio from a frequency response function v.s. transfer function

I'm trying to find the damping values of a specimen, based on sweeping the forcing frequency from 0-10 kHz. As shown in the diagram, I measure the input force from the shaker, and the subsequent response using an accelerometer on top. (The steel…
hopper19
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Relation between natural frequency and the thickness

If I have a solid material, let's say two bricks, one of which is thicker and I do modal/vibration testing. What would be the relation between thickness and natural frequency of any of them, is there any equation that can explain it, or does it…
elluthfi
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What can be the reason of the constant 50 Hz sound in my home?

I am suffering from a strange hum in my home. I have just bought my home and living in 3 months. A month ago I've started to hear a humming noise. Then, I recorded the sound and looked at its frequency response. The peak was at 50 Hz. After a while,…
Ufuk
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Eigenfreuency of beam

How would you calculate the eigenfrequency of such a cantilever?
james
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How to simulate the Natural Frequencies of a Planetary Gearbox?

I have a dynamical model of a planetary gearbox of the form: $\mathbf{M{\ddot q}+{\Omega_c}G{\dot q}+{[K_b+K_m-\Omega_c^2K_\Omega]q}=T(t)+F(t)} $ $K_b$: bearing stiffness symmetrical matrix $K_m$: mess stiffness matrix $K_\Omega$: diagonal…
spe4ker
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Definition of stiffness for structural dynamics: How would you find the stiffness of an unusual beam directly?

I have a structure which is essentially a curved beam (not an arch or anything simple) which I have modeled in microstran/spacegass. It looks something like this: Or for something more simple, imagine I have a beam like this: The definition of…
Noobie
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How do I study the frequency response of a physical system with Arduino?

I am a control engineering student and I am studying the frequency response of a system, so the Laplace domain, the Bode plot, poles, zeros,etc. ... I have clear grasp of their meaning, but if I think about the practice it is hard to grasp, at least…
dcr
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Mobile Frequency and Carrier Frequency not Matching

I am using a Google Nexus 6 Mobile in India with Airtel as Network Provider. Recently Airtel has upgraded their Network to 2300 Mhz 4G. Whereas Google Nexus 6 Operates on Band 3 (1800Mhz) LTE. When I switch Mobile to LTE Mode - I am able to use 4G…
Mitesh Manani
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Do internal / external stresses affect modal frequency?

Imagine a cantilevered beam, fixed on one end and with a tension line connecting the other end to ground (e.g. perpendicular to the length of the beam). If I increase the tension, does the modal frequencies of the beam change? On the one hand,…
user3533030
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