Questions tagged [vibration]
Vibration of mechanical systems is a field studied by mechanical engineers and civil engineers
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How to balance an irregular shape on a motor shaft?
I have an irregular shaped object about 100g in weight and 3x3x3 cm in size that I'd like to mount on a shaft (eg of a small motor) and spin. The trick is, I'd like it to be pretty close to perfectly ...
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what kind of Vibration Motor should I choose and how can I achieve my goal?
I'm building a vibration table for testing the durability of a metal rack, I want the vibration motor to create an even and average vertical displacement to the table, what kind of Vibration Motor ...
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Topology optimization issue (or not an issue, which is the issue)
I am currently doing some work in topology optimization regarding optimizing for the dynamic compliance of a beam structure but I am running into some issues. Well actually I am not running into some ...
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Controlled oscillation of a piano string by electromagnetic, mechanical, or other means
What would be a good way to actively control the loudness of an acoustic piano note over time after the note has already been struck by the hammer, such as by actively changing the amplitude of a ...
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Standing desk sway stabilization
I have a standing desk that sways when I'm typing and it is in the standing position. I've read numerous things online about this and can't find any actionable information for stabilizing the desk. It ...
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modal analysis of a wind turbine
I have to do a vibration mechanics project for university and I was thinking of doing the modal analysis of a wind turbine, only I don't know how to evaluate the results I get. With what I should ...
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How can I know the linearity/nonlinearity from the FRF result?
It's a FRF of neat PA 11 obtained by vibration test. (Mind that g is not a gram but the acceleration) Explanation says that for the excitation level of 5g, the FRF is strongly modified and the peak's ...
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What are the unknown sources of vibration in this Rotax 914 propulsion system
(This might be a little out of score for SE.Engineering, so close if appropriate.)
I have a drivetrain setup where I have been performing a vibration analysis.
Below is a diagram of the system. There ...
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vibration "amplifier" structure to place an accelerometer
I want to catch very small vibrations with an accelerometer.
Is there any structure that can amplify the vibrations, such as springs or something to place the accelerometer on?
The accelerometer will ...
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Boundary condition of vibrating flange in ANSYS mechanical
I have a structure with both sides a having flange. The vibration comes to plant from one of the flanges. The structure has it's own fixed support on its bottom, bearing its weight.
I assumed force is ...
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Do sound waves caused by a vibrating machines correlate to the vibration waves of the machine itself?
I'm a computer engineer, so please excuse my lack of mechanical knowledge :).
We have a machine that has large electrical motors causing massive amounts of vibrations, the machine also consists of ...
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Mechanism for fast vibration
What mechanisms can be used to apply fast vibration to an object? One way is this.
What are some other ways to do it?
I'm looking to go as fast as possible - 100s of Hz if possible.
Thankyou
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Effect of bracing on a music instrument top - is FEM modal analysis enough to predict this?
I'm currently building a music instrument (string instrument), and I am at the step where one applies certain braces to the soundboard. Since I actually don't know how the bracing will affect the ...
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Does Bending Stress Affect Natural Frequency?
I have been researching about the factors that affect natural frequencies, particularly about the effects of stresses.
Most of what I have found only discusses compressive and tensile stresses though, ...
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How can I measure RPM of an encased refrigerator compressor. I would like the resultant RPM reading as a variable DC output
I understand that there are very expensive meters that do this
; ex: Ono Sokki FT-7200 or FLuke, but I need a cheaper alternative.
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What methods can be used to stabilize a vibratory bowl used for orientation
I have a project where we are using a vibratory bowl to feed in parts to an assembler. The issue I am having is that the calibration sticker on the side is very out and a single line is very difficult ...
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Preliminary way to estimate damping quality factor (Q) from a SolidWorks FEM
I am analyzing the modal response of a structural FEM for a spacecraft structures course. I'm using Solidworks Simulation Premium. Need first mode to be above 40Hz and the damping Q-factor (quality ...
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How to measure the beat phenomenon in amplitude of vibration waveform?
I have time series of 3 signals, and I found the amplitude of vibration waveform would display the so-called beat phenomenon, which means the amplitude at different time is not always equal, and the ...
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How is the fundamental frequency of a large rotating body determined?
Okay, I understand that "large" is relative. I'm referring to the 60" diameter 5000 rpm counterrotating flywheels I've postulated in this question. When I was taking flying lessons in ...
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Can you explain mathematical and mechanics formulation of equation in Junker 1969 paper on self-loosening of fastener by vibration?
Can you help me to understand how the first equation in the paper 'New Criteria for Self-Loosening of Fasteners Under Vibration' by GH Junker, 1969 is derived? I'm not able to understand the ...
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(Why) does the sound of propeller planes change with increasing distance?
I recently heard a propeller plane, and then very shortly after a jet like noise. After I did some probability calculations, I conjectured that probably these two events are timely correlated.
I also ...
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What is the mechano-acoustic effect of off-centering the black paste on tabla-drum skins?
Tabla is a musical instrument composed of two drums, the Bayan (left on picture) and the Dayan (right on picture).
A unique feature of the tabla is the tuning [black] paste called the gab, applied to ...
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Understanding the units of columns in MaFaulDa Dataset
Recently I am learning about the MaFaulDa machine failure database. I am wondering about the unit of column zero (tachometer signal) measured by Monarch Instrument MT-190 (as announced by database ...
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Natural Frequency of a Shear Frame
Hi I've been stuck on a problem for one of my exam revisions, we were asked to identify the natural frequency of the following structures
I know that the equation for the stiffness is as follows
Left ...
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Sign Convention for Energy Methods in Vibration Analysis
Find the equivalent spring stiffness of the system below.
I was able to solve it using Newton's second law and got the result below.
$$ k_{eq} = \frac{mgl}{2} - \frac{k_1 l^2}{16} - k_2 l^2$$
However,...
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Contradiction of bandwidth and damping
I am studying control theory and mechanical vibrations.
From control theory aspect, I know that bandwidth and response time is inversely proportional, which means bandwidth and damping as well.
But in ...
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How does vibration monitoring with engine power differ?
How do engineers design vibration monitoring for motors with different wattage?
What effect does power have on vibration?
I consulted manufacturers of these vibration monitoring and did not see any ...
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Forced vibration single degree of freedom system
so for the Single Degree of freedom system, I obtained the equation in blue, where I think the equation below in black is missing the ‘m*a’ from F=ma?
So I see that there is one ‘m*a’, but is that ...
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Spring and damper in series, equation of motion
For the motion in fig 4.1 (a), please check the description of this system in the images above, everything should be there. I get it, assuming the positive direction is downward, the spring tension is ...
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frequency of oscillation of the disk
The mass m is suspended by a string from a disk
circular homogeneous of mass mc and radius R, as illustrated in figure 24. The disk is restricted from rotating by a spring attached to it at a distance ...
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"$\theta_A$" and "$J_A \theta_A$" in the opposite direction
The system represented in the figure is composed of two rigid assemblies articulated in
two points and connected to several springs as indicated. Each beam segment weighs 2 kgf/m, and the 5 kgf weight ...
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Positioning accelerometer on a cantilever beam
What is the appropriate position to place an accelerometer, along the length of a cantilever beam, for the follwing two cases:
The beam is under sinusoidal excitation at the free end.
The beam ...
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Dynamic equilibrium equations
The system represented in the figure consists of a 2 kg pulley to which two springs and a rigid square with 10 kg/m are connected, which in turn is articulated at point B (System is in the xz plane).
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Net force exerted by spring
I want to find the exact net force exerted by the spring between pt. P and C, when it is compressed till point P with some mass, m attached to it and released (assuming spring goes to pt. C after its ...
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Calculate Vibration Velocity and Acceleration from Triple Axis Accelerometer
Looking for very specific support developing a simple Python script to take the time series X,y,z tuple readings from a triple axis accelerometer and output a meaningful measure of vibration for ...
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Resonance of 4 cylinder engine
Let’s say I have a 4-Cylinder, in-line engine where all pistons start from the same point,
Could I have more than speed where resonance occurs?
I read on a book that systems have more than one natural ...
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Total Kinetic Energy of a System with a Body Inside Another for Lagrange's Equation
Suppose a bus with mass $m_1$ moving horizontally with velocity $\dot{x}_1$, and a person with mass $m_2$ running with velocity $\dot{x}_2$ inside the vehicle. What is the total kinetic energy of the ...
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Equations of Motion for the Multi Degree of Freedom (MDOF)
I was watching the video: Equations of Motion for the Multi Degree of Freedom (MDOF) Problem Using LaGrange's Equations from Good Vibrations with Freeball
However, I didn't understand how to obtain ...
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natural period of vibration for the system - positive and negative work
A 10kg block is suspended from a cable wrapped around a 5kg disk, as shown in the figure.
If the spring has a stiffness constant of k=200N/m, determine the natural period of vibration for the system
...
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Unbalanced forces on an Engine
so I have a 4 Cylinder inline engine configuration.
How would I identify the speeds at which vibrations due to unbalanced forces are acting?
I have data such as RPM and Force and Moments acting
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Particular Solution of Multiple-Degree-of-Freedom Systems
I was going through some Vibration examples on how to solve multiple-degree-of-freedom systems and I have noticed that they usually assume a particular solution with just one trigonometric function (...
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How can I find the right resonant frequency of a chassis?
Structures have infinite DOFs, so it possess infinite mode shapes. How can we find the right resonant frequency out of the infinite resonant frequencies so that we can save our structure?
For example, ...
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A problem from Damped free Vibrations
Problem:
I can understand the problem physically that the block is pulled by some amount X so that its displacement at t=0 is X. It is then released from that position so that its velocity at t=0 is ...
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How to analyse results of vibration isolation test
I performed some tests with vibration isolators and have computed the PSD. The natural frequency of the isolators is 110 Hz in the axial direction. So my question is, should I expect to see noise ...
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how to interpret plots in ISO 10816-8?
In ISO 10816-8 for reciprocating compressors, there are some plots that show the allowable RMS vs. frequency for every part of a compressor.
However, in the text of the standard, it is mentioned that ...
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Interpretation of results in a spring mass dashpot system subjected to harmonic excitation force
Consider a spring mass dashpot system subjected to a harmonic excitation force of
$$F(t)=F_0 sin(\omega t)$$
The response of a system assuming sufficient time has been passed and the complementary ...
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Control System Response
How does one find the zeta value or the frequency of an over damped response curve. I am used to determining things by using the log-decrement equation. Does that apply here even though there is no ...
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Force Transmitted to the support (Vibrations)
Consider the spring mass dashpot system shown below which is acted upon by a harmonic excitation force F(t). The reference is taken at the equilibrium position of the system when no F(t) was present. ...
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What is the best time interval in condition monitoring programs for checking rolling bearings?
The time intervals between observing or measuring the vibration of rolling bearings in industrial plants are so important in condition monitoring programs. For instance, some experts measure the ...
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Where does all the inherent vibrations in an internal combustion or jet engine come from?
I am trying to understand that why does a piston engine produce vibrations? What is the source of it and how will it cause the whole internal combustion engine to vibrate in response? Will jet engines ...
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