Skip to main content

Questions tagged [vibration]

Vibration of mechanical systems is a field studied by mechanical engineers and civil engineers

61 questions with no upvoted or accepted answers
Filter by
Sorted by
Tagged with
5 votes
1 answer
354 views

Mechanical vibration of objects

Do you happen to know relevant references in the literature that model the mechanical vibrations of a solid object (preferably antennas) by means of complex representations as a function of time?, i.e....
Jeremy's user avatar
  • 51
3 votes
0 answers
44 views

I don't understand a simulation result of frequency vibration analysis of ultrasonic tranducer

I am building a ultrasonic transducer like this (with double-exponential (75%-25%) match and 2 ring PZT8 50x20x6.5 (for the moment I do not take account of pre-stress on bolt) : When I simulate the 2 ...
rdpdo's user avatar
  • 31
2 votes
0 answers
64 views

Effect of frequency resolution on the frequency spectrum of impulse force delivered by an electromagnetic shaker

this is a part of my parameter study for the experiment (a vibration analysis with a force impulse input). This specific part studies the frequency resolution effect on the spectrum. The input (i.e.: ...
ComradeH's user avatar
  • 175
2 votes
0 answers
79 views

How to compare two acceleration sensors side-by-side?

I have a single axis analog capacitive acceleration sensor (from PCB Piezotronics) which is very reliable but expensive. Now I need more axis, unfortunately can not afford buying anymore. So I have ...
stardust's user avatar
  • 121
2 votes
0 answers
149 views

Determining the load on a pump vibration isolator

It seems to me that pump vibration isolators need to support: The weight of the pump The weight of the water in the pump The weight of the water (only) in the drop to the pump The supplier of ...
Use Linux 42's user avatar
2 votes
0 answers
35 views

Plot zero-pole from frequency response matrix

I've represented with Matlab a system with three degrees of freedom. I'm trying to plot a pole-zero map from my Frequency Response Matrix H(w) in the case of Damped-...
alb084's user avatar
  • 21
2 votes
0 answers
114 views

Combining critical speeds for a shaft of variable cross-section

I am looking to determine the critical speed for a shaft with universal joints at each end, where the halves are joined by telescoping profile members. I can calculate the critical speed of each ...
Trevor Archibald's user avatar
2 votes
0 answers
5k views

How to get mass normalized mode shapes?

I have an MDOF system with 4 degrees of freedom with forced input at one of the dof (4th dof)(it is a sinusoidal wave with a particular frequency expected to be generated using a shaker); displacement ...
Chaitanya Krishna's user avatar
1 vote
1 answer
68 views

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 ...
Kenn Sebesta's user avatar
1 vote
3 answers
164 views

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 ...
Rikus Coetzee's user avatar
1 vote
0 answers
81 views

On rectangular section beam properties of plate stiffeners

I am trying to understand the expression of the vertical dynamic stiffness $K_T$ and the rotational dynamic stiffness $K_r$ which appears in this paper where they consider a semi-infinite plate ...
Rann's user avatar
  • 11
1 vote
0 answers
82 views

Ride Comfort Estimation using Accelerometers

I've been trying to find established/novel methods for calculating ride comfort using accelerometers and recently I came across this paper which uses ISO 2631 standard to get an objective measure of ...
MajorMajorMajorMajor's user avatar
1 vote
0 answers
138 views

Shell Breathing Modes and Base Excitation

I have been reviewing "Vibration of Continuous System" by S. Rao as part of self-studying to help with work. I started reviewing the chapter regarding shells and noticed that shells have ...
ganondorf29's user avatar
1 vote
0 answers
37 views

Can concepts like “critical damping” or “resonant frequency” be applied to more complex systems than just a spring and damper in parallel?

I am trying to do some modeling analysis by representing materials with parallel systems of springs and dampers. In the simplest case with just one spring parallel to a damper, we have the traditional ...
mike's user avatar
  • 161
1 vote
0 answers
82 views

How to state the PSD value (random vibration)

In random vibration analysis, the load is given as a PSD (power spectral density). The values are often $G^2/Hz$, but I have an example where the PSD is a pressure $Pa^2/Hz$. The value is written as $(...
JohnHoltz's user avatar
  • 526
1 vote
0 answers
189 views

Modelling acoustic instruments — predicting frequencies, decays, levels, and phases of modes of a circular membrane (drum head)

I have been working on some acoustic synthesis software for modelling several acoustic instruments. I am using the principle of modal synthesis, where every mode of vibration is individually ...
mike's user avatar
  • 161
1 vote
0 answers
4k views

Equivalent spring of beam supported by springs

My professor gave us yesterday a problem to calculate the equivalent spring of the system shown in the attached figure. The problem: a cantilever beam supported by two springs $k_1$ and $k_2$ located ...
Thales's user avatar
  • 126
1 vote
0 answers
25 views

How to find the maximum misalignment from vibration?

Consider the system in the (drawn in Paint) image. Assume that there is an input acceleration at the ground defined by a PSD. This acceleration can be in any axis. Points A and B are initially aligned ...
pshlady's user avatar
  • 253
1 vote
0 answers
44 views

Applying modern control systems to real mechanical engineering problems

My aim was to damp the vibration of a stepper motor ( Nema 8 ) using only spring systems. I have taken modern control course and I wanted to apply it here. So I first analyzed my open loop system and ...
Socrates Gebremedhin's user avatar
1 vote
0 answers
34 views

Why does Experimental Modal Analysis need a reference signal?

I need to conduct a vibration experiment with 3 accelerometers for a gear box. I'm reading the theory of mainly how to perform the vibration analysis but I don't understand why EMA needs a reference ...
spe4ker's user avatar
  • 409
0 votes
0 answers
24 views

Some questions at interpreting FRF from vibration test

Currently going through impact hammer test of cantilever beam(200mmx20mmx2mm) which is made of particulate composite(Epoxy/PZT/CB). Hammer sensitivity is 2.25mV/N and accelerometer sensitivity is ...
KIM's user avatar
  • 1
0 votes
0 answers
44 views

Vibrating hollow sphere

I would like to make a hollow sphere that can vibrate like a tuning fork. It should go like this: Place the sphere on a table Strike the sphere with something like a spoon The sphere vibrates (...
Riemann's user avatar
  • 121
0 votes
0 answers
34 views

How would you handle the rebalancing of a bearing cage?

I am a intern who was tasked with finding the correct amount to mill off (in an angle) of a bearing cage (basically an annulus with gaps in it to hold the balls or rollers) to bring it back into ...
Anon's user avatar
  • 1
0 votes
0 answers
34 views

Is there explicit expersion for the natural frequency of a cantilever timoshenko beam?

I am trying to find a closed form solution for the natural frequency of cantilever Timoshenko beam. In mechanical vibration (Rao, 5th edition) he outlined the details to include the Effects of Rotary ...
AlFagera's user avatar
  • 113
0 votes
0 answers
33 views

Finding the best fit between Ansys model results and measurd values to optimize the parameters

I have the final element model of an experimental rig respresenting a vibrating system. The time domain results from both are known. I need to reduce the error between the results/find the best fit ...
Murali's user avatar
  • 1
0 votes
0 answers
31 views

How to Design System for Resonating Tuning Forks from Base

I have seen videos like this where two tuning forks with matched frequencies are attached to resonant chambers and the sound from one fork can be used to resonate the other fork. I am interested in ...
Emmett Palaima's user avatar
0 votes
0 answers
64 views

Induce vibration on metal ball

Suppose that I have a hollow, metal ball that lies on a table. How do I induce a vibration on this ball? I want to be able to control the frequency, so it is a forced vibration (not natural vibration)....
Riemann's user avatar
  • 121
0 votes
0 answers
31 views

Ansys Pedestrian-Induced Vibration on Bridge

I have a concrete girder box bridge that is 40 m long and 4 meters wide, and I would like to simulate the response of the bridge using Ansys random vibration for pedestrian traffic. What are ...
James's user avatar
  • 1
0 votes
0 answers
19 views

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 ...
Loo's user avatar
  • 1
0 votes
0 answers
64 views

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 ...
DVL's user avatar
  • 1
0 votes
1 answer
63 views

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 ...
Galbert's user avatar
0 votes
0 answers
20 views

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 ...
gaaarden's user avatar
0 votes
0 answers
40 views

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 ...
arisk4's user avatar
  • 1
0 votes
0 answers
13 views

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 ...
mohammadsdtmnd's user avatar
0 votes
0 answers
37 views

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 ...
Teyash Arjun's user avatar
0 votes
1 answer
80 views

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 ...
D. Hodge's user avatar
0 votes
0 answers
57 views

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 ...
WUYing's user avatar
  • 1
0 votes
1 answer
117 views

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 ...
Khushal Badhan's user avatar
0 votes
1 answer
313 views

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 ...
Tym's user avatar
  • 1
0 votes
1 answer
111 views

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 ...
Batsova's user avatar
0 votes
2 answers
158 views

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 ...
Kane's user avatar
  • 11
0 votes
1 answer
64 views

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 ...
Iuri's user avatar
  • 15
0 votes
0 answers
64 views

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
Roger's user avatar
  • 1
0 votes
1 answer
178 views

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 ...
Ali Hosseinli's user avatar
0 votes
0 answers
26 views

Adding tension to a model of a Timoshenko beam?

I am interested in modeling a Timoshenko beam: https://en.wikipedia.org/wiki/Timoshenko%E2%80%93Ehrenfest_beam_theory However, I would also like to add tension to the beam so that it can vibrate like ...
mike's user avatar
  • 161
0 votes
0 answers
33 views

Model for dynamic plate deformation

I would like to gather ideas to model the dynamic behaviour of a plate with variable thickness. The assumption are: Small deformations. The plate is all made of the same material with variable ...
Worldsheep's user avatar
0 votes
0 answers
548 views

Boundary Conditions of a Stepped Beam

I would like to ask about the boundary conditions to be considered in a stepped beam. For a cantilever beam wherein the one end is fixed while the other end is free to oscillate along the z-axis, we ...
p.laine's user avatar
0 votes
0 answers
92 views

Is there an analogy between mechanical vibrations and electromagnetic waves

Recent questions about analogies between mechanical and electrical systems and about electromagnetic waves from a conductor made me wonder whether there is an analogy between the mechanical vibrations ...
NMech's user avatar
  • 24.4k
0 votes
0 answers
20 views

How do you exclude the connections between mechanical shaker and specimen?

to apply any kind of vibration, shock input using a mechanical shaker to any specimen, you first need to connect the speciment to the shaker, that sometimes needs some connectors that could weight as ...
FabioSpaghetti's user avatar
0 votes
0 answers
2k views

How to use Spectroid app to measure low frequency vibrations?

I need to measure how low frequency (vibration) changes when going through different materials. The only possible way I found is by using Spectroid app. However, I have no idea of what settings to set ...
NightRider's user avatar