Science topic

# Vibration - Science topic

A continuing periodic change in displacement with respect to a fixed reference. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)

Questions related to Vibration

I want to calculate the angle between C=O and C=C symmetric and asymmetric vibrating mode of phenol. I was trying to calculate by using DFT calculations but could not do it? please help.

During the operation of industrial hoists an external mechanical vibration happened using two synchronous motors (master and follower)?

Is it solve this problem?

During commissioning activities a static equipment was subject to sever vibration and high acoustic sound vibration. Although operated within the design normal operating parameters.

This is a boundary control problem of a hybrid ODE-PDE system. The system consists of an actuator, a flexible link fixed to the actuator, and a tip mass at the free end of the link. In most literature, two control inputs are used for the simultaneous position and vibration control of the said system: One is the actuator's torque and the other is a force at the tip mass. The application of a control force at the tip mass of a manipulator does not seem to be a practical solution. Can we use only the actuator's torque to simultaneously control the position and vibration of the beam and the tip mass?

I would be grateful to anyone for sharing any theorem or paper addressing this issue (in support or against).

Thank you!

Greetings everyone, I have recently found a contradiction between the two usual ways of calculating energy barriers for a chemical reaction. Usually, following the Gaussian whitepaper, I take the different reactants in separate calculations. (https://gaussian.com/wp-content/uploads/dl/thermo.pdf)

But I have found a free energy value for a reaction which made me suspect that this method might not be correct (I will describe it below). Following this suspicion, I found this other Orca guide, (https://www.orcasoftware.de/tutorials_orca/react/actibar.html) where they do the calculation with the reagents together (although this would really be the vdW complex, which will always be a few kcal/mol lower). Analyzing the output of the vibration calculations, I realized that the reagents separately tend to miss a few kcal/mol compared to the combined calculation, with both reagents at a long distance. The electronic energy matches, but the free energy therefore does not.

The reaction that I am studying is a reduction of a hydroperoxide with phosphine/phosphite, experimentally it is a fast reaction and therefore I expected a low reaction barrier, however, following the Gaussian method, the free energy barrier is 25 kcal /mol. Following Orca's guide with the same calculation, the barrier is 15 kcal/mol, closer to what is expected (with other DFT functionals it is even lower). The calculation method is M062X/aug-cc-pVTZ, which itself should be accurate to within 1-2 kcal/mol.

In these cases, the usual thing is to think that oneself is wrong, but being the contradiction between two guides provided by two of the best known software in this area, it is possible to think that there is something that is not being done well. In addition, it is a detail that is not usually mentioned in the methods of most publications, so it is difficult to know which guide each researcher follows.

Best regards and thanks in advance,

Pablo Ortega

Which is the most crack direction is studied in a metal cantilever beam? When the crack is vertical or horizontal? (I mean if the crack propagates vertically or horizontally?)

And how each type of excitation(Bending, Axial,..) is sensitive for each type of crack shape and orientation?

I am asking for test purposes .. So I can use the crack direction that is more sensitive for measurements in my experiment.

How can I get the second and third natural frequency of a cantilever beam experimentally??

The problem that I am facing is that I got only the first natural frequency.. I can't get other frequencies..

I am trying to use vibrotactile feedback to convey information, using LRA-actuators on a glove that operate at a fixed frequency of 205Hz. By adjusting the amplitude I try to convey the information.

Let's assume we have a given range of amplitudes I can use (e.g. 0% to 100%). I wonder how big the steps have to be for a human to notice the difference in a decrease or increase in the perceived intensity. (e.g. if I trigger four actuators in sequence, how huge do the gaps between the amplitudes have to be set, to be perceived as a decrease or increase compared to the previously felt vibration)

I get a peak at 240 Hz in FFT plot of tool vibration. The accelerometr is placed at 45 mm from tool tip during machining. Turning of nickel steel of dia 60 mm and length 300 mm at spindle speed 256 RPM. PCLNR2020K tool holder. Panther conventional precision lathe it is.

Hello,

I need to extract mode shapes and damping ratios from ambient vibration measurement we have performed on a dam (2 setups with 6 sensors). Would you have any suggestions for an open source code that works well to perform such analysis (a code with similar capabilities than the commercial software Artemis)?

Thanks

Hello,

The model that I am working on is basically a long hollow tube including many small cylinders that initially in contact with the inner surface of this tube. However, these cylinders might disconnect or breakage from the tube surface when it is subjected to an external impact loading or a vibration. So, I am trying to find a contact feature that including a failure criterion between these cylindrical surfaces and the tube surface. I have found a keyword in LS-DYNA so-called “*CONTACT_TIED_SURFACE_TO_SURFACE_FAILURE” that simulate this kind of contact interface problem; however, I have to do this analysis using ABAQUS and thus I am looking for a similar keyword in ABAQUS. Any help in defining this kind of contact interface using ABAQUS, will be highly appreciated.

Thank you

Belal

What is lattice mode in RAMAN vibration mode?
In general, can you help me about what the lattice mode is in the RAMAN analysis?

I'm working on Sb2S3 thin films. During the Raman analysis, I saw that there are lattice mode vibrational modes. How is it different from symmetric S–Sb–S stretching or symmetric S–Sb–S bending? In General, can you help me about what the lattice mode is in the RAMAN analysis?

I understand there will be exact multiple of fundamental frequency based bearing rotation with respect to fundamental, based on gear rotation with respect to fundamental. But what exactly means for multiples of bearing rotations, multiples of blade passes like 1x, 2x, 3x etc.,

i need some helping material regarding hilbert transform and empirical mode decomposition. i want to apply on my vibration signal to evaluate the frequency at different phases of the signal. i am using EMD in matlab. if there is some kind of code regarding this kindly share. i want to ask some question related to EMD and hilbert transform

i will be thankful

There are a lot of software for modeling vibrational spectra, but what is the best one? There are two major branch of software: firs principal (ab initio) and semi empirical. I'm interesting the both. The "best" means is the software gives the relevant result comparing with experimental spectra.

I‘m doing some research about time-varying cable forces. I need some data about cable vibration. Where can I find the data about cable vibration ?

Dear researchers,

I am just trying to vibrate a plate with a horn (see attached figure) in one direction with ultrasonic vibrations in Abaqus. I am new to Abaqus,

**how can I apply an external vibration/vibrational load to surface of a plate**? Harmonic analysis needs a force but can I manipulate it as a vibration? I am open to any suggestions.as i had done this in ansys so how can i verify my result as my project head said to verify whether it is correct or not please help

The stress strain curve of rubber is not linear and follows a curved line both as the strain increases and as it decreases again. Does this hysteresis lead to formation of harmonics or other non lienar phenomena in eg a vibration insulated system?

Hi everyone,

I want to extract the global mass and stiffness matrices of an Abaqus modal analysis, so as to post-processing it with Matlab.

I have already read many comments on RG regarding this question and added the following lines at the end of my Input file to get the mass and stiffness matrix.

*STEP

*MATRIX GENERATE, STIFFNESS, MASS

*MATRIX OUTPUT, STIFFNESS,MASS,FORMAT=MATRIX INPUT

*END STEP

So far, everything is fine.

I have also written Matlab code that works perfectly for 3D solids or shell elements, but not when both solid and shell elements are together.

In my model, I had to use both solid and shell elements in Abaqus. Looking at the mass and stiffness matrices, I saw that there are 3DOF per node for solid elements and 6 DOF for shell elements, so I cannot use the attached Matlab code as the model has 3DOF for solid elements and 6DOF for shell elements.

My mass matrix looks like this:

1,1, 1,1, 5.115770202111807e-10

1,2, 1,1, 4.923414202110917e-12

1,3, 1,1, -5.733085750203833e-15

2,1, 1,1, 1.453330463639921e-11

2,2, 1,1, -2.461707101055460e-12

2,3, 1,1, 2.866542875101822e-15

1,4, 1,4, 4.295511112920469e-14

1,5, 1,4, -4.054846090561977e-14

1,6, 1,4, -8.889774326370160e-16

2,4, 1,4, 1.225209356335630e-14

2,5, 1,4, -1.103358818158063e-14

2,6, 1,4, -4.552490123962178e-16

...

131010,1, 131010,1, 6.793914400596321e-08

131010,2, 131010,2, 6.793914400596321e-08

131010,3, 131010,3, 6.793914400596321e-08

131011,1, 131011,1, 7.423556175182037e-08

131011,2, 131011,2, 7.423556175182037e-08

131011,3, 131011,3, 7.423556175182037e-08

As you see here, some parts have 3DOF and some parts have 6DOF. Some parts are like a lumped and some parts are like a consistent mass matrix.

In this case, how can one use Matlab in order to get a global stiffness and mass matrices from this?

I've been struggling with this problem for a long time and still haven't been able to solve it.

Here, I am attaching both the mass.mtx file and the Matlab code.

Any help would be appreciated.

function [matlab_matrix] = import_matrix(mtx_file)

%============== Import Stiffness Matrix ==============%

abaqus_stiffness_matrix = dlmread(mtx_file);

% merge node number info from column 1 and DOF info from column 2 and

% store in the 1st column of a new matrix

%If number of DOF are 2,multiply by 2.

matlab_nodes(:,1) = 2*(abaqus_stiffness_matrix(:,1)-1)+ ...

abaqus_stiffness_matrix(:,2);

% merge node number info from column 3 and DOF info from column 4 and

% store in the 2nd column of a new matrix

matlab_nodes(:,2) = 2*(abaqus_stiffness_matrix(:,3)-1)+ ...

abaqus_stiffness_matrix(:,4);

% extract the stiffness values from the .mtx file, and store in a double

% length vector

stiffness_values = [abaqus_stiffness_matrix(:,5); ...

abaqus_stiffness_matrix(:,5)];

% create a matrix of the new matlab node numbers, and a vector of indices

% of their position in the abaqus stiffness matrix

[matlab_matrix_indices, abaqus_stiffness_value_index] = unique( ...

[matlab_nodes; matlab_nodes(:,2) matlab_nodes(:,1)], 'rows');

% compile the stiffness matrix using the new node numbering convention

matlab_matrix = accumarray( matlab_matrix_indices, ...

stiffness_values(abaqus_stiffness_value_index), [], @max, [], true);

What Is The Relationship Between Vibration Of The Chest Wall And The Resulting Chest Wall Forces, Chest Wall Circumference, Intrapleural Pressure, And Expiratory Flow Rate?

I am collecting some data from the machines through sensors (like vibration, temperature, etc.) for predictive maintenance purpose. But there is no any "historical failure data" yet to establish a machine learning algorithm and predict the next failure, etc. So, how can i make PdM or which other methods&algorithms can i use in the beginning for this purpose?

what could be the vibration band mode of intense 2440 cm-1

the main substance is phosphate, potassium, magnesium, and water molecule.

What is its unit of measure?

How can it be calculated?

How can it be used when shaking the tree stem?

Can anyone suggest to me method to design fuzzy inference system (FIS) for MIMO structural damage detection (i.e. data distribution on the membership function, parameters of MF, Generate rules ... etc )

In my system there are 3 inputs and 2 outputs:

Inputs: Relative 1st Natural frequency , Relative 2nd Natural frequency , Relative 3rd Natural frequency

Outputs: Crack depth ratio , Crack Length

Note: I tried to use "genfis" By MATLAB it didn't give me reasonable results.

Hello,

The fist mode shape (Out of plane) of my MEMS chip occurs at 7.7 MHz. there is released cantilever in my chip and I would like to vibrate it to its resonance frequency. What method do you suggest to actuate the MEMS chip? If you have any product in your mind I appreciate that if you send me the link as well.

Best

Masoud

I think, Both FTIR and Raman Spectroscopy give the information about vibration of molecules/atom and stretching of molecules/atom or lattice vibration then what is the main difference between both Spectra (FTIR and Raman). Is there any difference between them?

Generally, in literature (from what I've read), to monitor conditions of mechanical rotating drivetrains connected to an electric motor are used accelerometers. Or in the case of short drivetrains also the current signals can be significant to detect anomalous torque load oscillations related to a mechanical fault. In the case of nonstationary conditions (not constant speed of the electric motor), the Computed Order Tracking (

Article Analysis of computed order tracking. Mech Syst Sig Proces

) is a technique that is able to extract Orders of the rotor speed in vibration signals even when the speed change over time. In that way, is possible to relate each component that rotates at a known, fixed rate with respect to the motor rotor, and detect unwanted vibrations.

Could I apply the same technique for electric signals? If I have an electric motor with a speed reducer attached with a damaged bearing running at varying speeds, once acquired the one-phase current signal and the rotor speed feedback, if I apply a resampling of that signal with respect to the angle (as in the Computed Order Tracking for vibration signals), would I be able to detect speed Orders that can be related to the defecting bearing? In literature, there are no papers that apply COT to electric signals (or at least I haven't found it), which is the reason? This technique would be ineffective? There are some resolution limits? Or depends on the fact that electric signals are rich in frequency content related to the supply and mechanical oscillations are too weak to be detected?

We would like to use Polytech microsystem analyzer (MSA) to characterize the resonance frequency of a fabricated cantilever and compare them with FE. However, the stage of the MSA is passive and we need an actuator to vibrate the cantilever to its resonance frequency. What would people use in such situations? Is there any commercial actuator for this purpose? Or do people design them according to their purpose?

Of course, set the damping ratio of a structure to 5% will simplify the dynamic calculation. However, we all know it is just an assumption and since structures are quite sensitive to their "real" damping ratio, especially when the frequency ratio is near the unit. I wonder how we can achieve an actual damping coefficient numerically?

Are there any theoretical methods and/or literature available to carry out flow induced vibration study of orifice in a pipe.

If so can you please share the same?

There are different empirical equations and techniques like Fuzzy, ANN, etc.. for predicting Blast Induced Ground Vibration. In addition to these is there any software for predicting Blast Induced Ground Vibration

It is appreciated if you recommend a benchmark study with the available dataset for video processing.

A flexible beam has vibration, we want to eliminate its vibration using an active arm jointed to free end of the flexible beam.

Hi all

I am simulating a diaphragm structure sensor. I want to give the excitation as sinusoidal displacement whose amplitude will be fixed but frequency will be varied. when I apply the boundary load(N) and run the simulation for frequency domain study it gives expected output. but I want to give a displacement excitation(m )(or we can say sinusoidal vibration) to that boundary. Can anyone please help me to do this task?

I have been working on 1D and 2D materials; now, I would like to measure the vibrational properties using the Raman spectroscopy of these samples in the liquid state measurement.

I have question regarding to 1d cantilever beam problem which is divided to five elements.

I want to reduce the degree of freedom for each node to 1(just keep uy)instead of 6.

I added fixed support in the first node and applied displacement on each other nodes( make it freely translate in y direction)

But it still gives me results for 6 dof for each node.

My goal is to get only 5×5 MK matrices but it gave me 30*30.

Anyone knows how to fix this problem?

Hello Everyone,

We have recently investigated a Semi-Supervised Deep Learning approach for anomaly detection of Wind Turbine generators based on vibration signals in the paper entitled "Anomaly Detection on Wind Turbines based on a Deep Learning Analysis of Vibration Signals" [1]. We found that vibration data enables a promising mechanism to detect abnormal behavior on wind turbines with a careful Machine Learning pipeline design. The paper presents an IoT-ready Machine Learning pipeline that encompasses data gathering, preprocessing, feature extraction, and classification. The approach is based on a Semi-Supervised Deep Learning approach, using Deep Autoencoders combined with a normality threshold selection based on the F1-Score analysis for a labeled data-set. The vibration data is preprocessed with band-pass filters and DC-component removal, rotation speed relation, and FFT. Finally, 11 features are extracted, from minimum, maximum, RMS, and standard deviation, to kurtosis, shape factor, energy, and entropy. The trained detection model achieved accuracy >99%, precision >97%, and recall of 100% for the evaluated data-set.

Moreover, with the IoT integration, the proposed workflow can notify users whenever abnormal behavior is noticed. What do you think about our findings? For more details, check the full paper at . If you have similar experiences with anomaly detection in rotating machinery, or if you have any comments or questions, feel free to leave a comment so we can start a fascinating discussion.

[1] José Luis Conradi Hoffmann, Leonardo Passig Horstmann, Mateus Martínez Lucena, Gustavo Medeiros de Araujo, Antônio Augusto Fröhlich, and Marcos Hisashi Napoli Nishioka, Anomaly Detection on Wind Turbines Based on a Deep Learning Analysis of Vibration Signals, In Applied Artificial Intelligence:9, 2021. DOI: 10.1080/08839514.2021.1966879.

Best Regards,

José Luis Conradi Hoffmann

Software/Hardware Integration Lab

Federal University of Santa Catarina, Florianópolis - SC, Brasil

Dear Researchers.

I am studying the vibration of twisted blade under rotation using scanning head PSV 500 .

We positioned the LDV to be in front of the blade . dispositions is available in the attached picture.

- The case is for the same blade but oriented in different manner.

the (x1) is the direction where the vibration appears in each case of blade disposition.

- I would like to know at each case how the vibrometry work and how it gives the results. is there any need to re-position it.

any types of vibration which can be discussed with nonlinear oscillation

We are using a horn-type ultrasonic transducer for cavitation and cleaning purposes.

We experimentally found that the cavitation effect and cleaning effectiveness were decreased when input power was higher than a certain value.

The sound pressure measured by the hydrophone showed a periodic wave pattern when we applied proper input power, but it showed an irregular wave pattern when the input power is high (maximum value of sound pressure was high, but RMS value was low).

I have two questions

1. Does cavitation is promoted when the acoustic field shows a uniform and periodic pattern?? (even the maximum sound pressure is lower). Why??

2. Does the tip of the ultrasonic horn irregularly vibrate when high power was applied?? If not, why does the measured sound pressure showed an irregular pattern??

The vibration sensor (e.g. accelerator) is commonly used to monitor the vibration signal of a bearing for condition monitoring and fault diagnosis. If there any Standard for bearing vibration signal monitoring?

Hello everyone,

I'm trying to model the motion of a cylinder in both CF and IL directions, but the UDF code that I have only can move the cylinder in the CF direction. Sadly I have never had the chance to learn to code UDF. Can someone please help me?

I will share the code below.

I really appreciate any help you can provide or at least promote this question to find the best answer to my issue.

FYI, this code is for Vortex-Induced Vibration of cylinders

####################################################

#include "udf.h"

#include "dynamesh_tools.h"

#include "unsteady.h"

FILE *fout;

static real v_prev;

DEFINE_SDOF_PROPERTIES(stage,prop,dt,time,dtime)

{

Thread *t;

Domain *d=Get_Domain(1);

real x_cg[3],force[2],moment[3];

real cg; /*Center of gravity position*/

real vel; /*Cylinder velocity*/

real Fy; /*Lift Force*/

real mass=8.88; /*Cylinder mass*/

real fn=1.06; /*System frequancy*/

real wn=2*M_PI*fn; /*System angular velocity*/

real z=0.002; /*Damping coefficeint*/

real k=mass*wn*wn; /*System stiffness*/

real c=2*mass*wn*z; /*System damping*/

/*Get the thread pointer for this which motion is define*/

t=DT_THREAD(dt);

prop[SDOF_MASS]=8.88; /*System mass of the 6DFOF*/

prop[SDOF_ZERO_TRANS_X]=TRUE;

prop[SDOF_ZERO_TRANS_Z]=TRUE;

prop[SDOF_ZERO_ROT_X]=TRUE;

prop[SDOF_ZERO_ROT_Y]=TRUE;

prop[SDOF_ZERO_ROT_Z]=TRUE;

cg=DT_CG(dt)[1];

vel=DT_VEL_CG(dt)[1];

prop[SDOF_LOAD_F_Y]=-k*cg-vel*c;

fout=fopen("results.txt", "a"); /*Open file*/

/*Wrtie data into file*/

fprintf(fout, "%g %g %g\n",time,DT_CG(dt)[1],DT_VEL_CG(dt)[1]);

fclose(fout);

}

I'm trying to reduce a 3d printer extruder vibration. When the extruder starts to move, vibrates that decrease printing quality. How can I reduce the vibration? I need a procedure to solve the problem using FEM methods like Abaqus. The procedure should contain an optimization method.

I wish to understand whether it is possible to make a phonon mode resonate with an externally applied signal in a lab, and whether a laser can be used for the purpose (if not, is there any other source that will do the job?).

The vibration caused by a bearing is usually used as a key parameter to evaluate the health and operating conditions of the bearing. To achieve this purpose, a threshold value of vibration signal to distinguish the healthy and abnormal bearing is often required. How to set/determine a threshold value of a bearing in a specific application?

Hi everyone,

I'd like to inquire about the best method for monitoring the water level of a borehole with a depth of up to 400 meters. Although the depth of the boundary is unknown, it is assumed to be fractured diorite (upper) and diorite bedrock (lower). I've read about open standpipes and vibrating wire piezometers, but I'm concerned about their long-term reliability. It would be fantastic if you could contribute your practical ideas and opinions. I am open to ideas and eager to learn more from you. Thank you sincerely!

Best regards,

Raymond

Is there any defined radii ratio with respect to the plate thickness exceeding to which an annular plate may be treated as a ring? Moreover what changes in vibrational behaviour may be observed when we increase the radii ratio of an annular plate and make it a ring?

Hi!

I would love it if someone can explain how to read the vibrational frequency data listed in NIST website. For example, there are four vibrational modes (in cm

^{-1}) listed for Methane (https://webbook.nist.gov/cgi/cbook.cgi?ID=C74828&Mask=800), 2917 (symmetric stretching), 1534 and 1306 (both degenerate deformation), and 3019 (degenerate stretching) . Methane should have 3N-6 = 9 vibrational frequencies, so how do I know which of the above mentioned degenerate modes are doubly or triply degenerate? This website (https://lweb.cfa.harvard.edu/hitran/vibrational.html) mentions 1534 is doubly degenerate and 3019 and 1306 modes are the triply degenerate modes which makes up the 9 frequencies for methane. But it also mentions the following 12 modes for Ethane (2954, 1388, 995, 289, 2896, 1379, 2969, 1468, 823, 2985, 1469, 822) where the last 3 are stated as doubly degenerate. But that would still give us 15 frequencies instead of 18. NIST mentions almost similar frequencies for ethane (https://webbook.nist.gov/cgi/cbook.cgi?ID=C74840&Mask=800) but lists 2969, 1468, 2985, & 1469 as degenerate modes. Hence, my question is, how do I know which of the NIST listed vibrational modes are doubly or triply degenerate to make up the 3N-5 or 3N-6 frequencies for linear and non-linear molecules?Thank you so much!

Had tried lubricating and adjusted the position of the foundation, but they still vibrate.

When the motor and gearbox are unconnected with the sprocket, they won't vibrate. The motor and gearbox only vibrate when connected with the sprocket via chain.

clc;clear

fs=100; tspan=[1/fs:1/fs:50];

fi=linspace(0,fs/2,2*fs);

Am=10*exp(-linspace(0,20,length(fi)));

for i=1:length(fi);

x(:,i)=Am(i)*sin(2*pi*fi(i).*tspan+2*pi*rand);

end;

noise=sum(x')/length(fi); % noise data

signal=0.1*sin(2*pi*3*tspan).*sin(2*pi*0.5*tspan);

signal_measure=signal+noise;

% Question: how to seperate signal from signal_measure?

We have a one meter long copper pipe through which water passes at a certain speed. The outer wall of the tube is covered by the heater where all the energy of the heater is transferred to the tube. Now the outer wall of the tube is vibrated in a vertical direction by a vibrator using different frequencies up to 3000 Hz. We want to examine the rate of heat transfer at each of the vibrational frequencies at the end of the fluid.

**Which physics can be used to perform this analysis in COMSOL software?**

*(outer diameter of tube = 9.52mm / inner diameter of tube = 8.72mm / Speed of Fluid = 0.059m/s)*

I have a nonlinear ODE (second order) and exponential force in right side of equation ( q(t)=p

_{0}(1-t/t_{0})EXP[(-r*t)/t_{0}] ) . p_{0}, t_{0}and r are constant. I see in Nayfeh and Mook book only harmonic force. but i have a exponential force. How I can use from the Method of multiple scale to solve this problem?I am measuring the thrust of an electric thruster, but the data obtained is noisy. Because the thrust value is too small (micro N), it is greatly affected by factors such as temperature, vibration, and vacuum pressure. How to denoise the thrust data and eliminate those interference items?

I'm attempting to figure out how to organise the nonlinear stiffness matrices and entire solution technique utilising the generalised differential quadrature approach. Many research articles cite open literature, however, none of the researchers reveal how to organise nonlinear stiffness with linear stiffness.

This is just like the EAS of NDRRMC. It will strongly vibrate your phone for a bad weather update.

my cell line is THP-1 cell

that black dot moves or looks like vibration...

is it contamination??

Dear all.

I am using a Laser Doppler vibrometry to me measure the vibration of a structure, what I am doing now consist of exporting velocity to signal processing and integrate it to obtain Displacement but due to that an error will be always added to the results where the signal will be fluctuating around different value and even that (max-max) value remain correct but the shape of the signal is not as I am willing.

is there is a way to input directly the displacement by time? I read the guide but nothing there.

a lot of article could handle that but they did not show the way.

Please advice

Dear all.

Since I am working on the establishment of a Lab for vibration measurement and signal processing for rotating machinery, I would highly appreciate based on your experience what should be included (bought) as equipment.

Thanks all

Any structures like the bridge, railway suspension, beam, building. With damage occurred, it is expected that the vibration mode will be different.

I am interested in studying the vibration level classification to determine the damage to a machine using the

**random forest classifier**. Based on the accuracy and computational cost, what is the best**feature extraction**method that can be used in this case?So I am beginner in Random vibration research. I have gone through some theory like ergodicity, stationarity, PSD etc.. related to Random Vibration. I am trying to model a very basic SDOF system subjected to random vibration.

I am trying Python. I have already modelled a harmonically loaded linear vibration system. For that I just needed to solve the equation of motion. But I am confused regarding incorporating randomness. How and where I use

How can I move about ? What are the baby steps that I should take ?

Hello

I am working with piezoceramic actuator to vibrate the flexible substrate but I am confused how to determine the resonant frequencies under loading condition? I am using function generator and amplifier and observe the vibration from the oscilloscope. I know that Network analyzer would help to determine the resonant frequency. But how to do that using NA, if anyone knows, please help.

Why vibration levels under certain defect condition get reduced than healthy state vibration ?

In the Graph below

Blue line represents healthy state vibration of a machine

Red line represent the defect state of the machine

I need the basics for including energy loss in Hamilton formulation for Finite element analysis for vibration of viscoelastic materials. The papers I read use complex modulus to represent viscoelastic losses or convolution integrals. Can someone give me a link where the formulation starts from Hamilton's principle?

Hello everyone

I want to use the finite element method to solve the differential equation of the bending vibration of a euler bernouli beam you can recommend me the most efficient version of the finite element method

Hi all,

As far as I know, to distinguish the

**core-mechanism of UV-Vis spectrum and Raman spectrum**, we can attach**UV-Vis spectrum with Oscillation**and**Raman spectrum with Rovibronic State**(**Ro**tational -**Vibr**ational - Electr**onic**State) word.However, I am having a vague distinction between Oscillation in the UV-Vis spectrum and Vibration in the Raman spectrum.

Can you clarify this for me?

The system should generate high-frequency vibration. I want to component or mechanism use to generate.

Can anyone suggest how to calculate what type of bands present in the sample if we collect Raman spectra?

Recently I take the Raman spectra of my sample it shows three intense peaks in the range of 180, 570 and 640 and one small peak around 400 so how to interpret this and what type of vibration present in the sample?

I want to calculate vibrational reorganization energy for the ground and excited state, associated with corresponding normal modes.I also want to plot reorganization energy Vs frequency .I have attached one such example. Can anyone suggest me how to calculate vibrational reorganization energy with normal modes using gaussian ?

Thank you in advance.

Can the current and voltage generated by the piezoelectric vibratory energy harvester be measured experimentally?In other words, can we measure the power generated by the piezoelectric vibration energy collector ？

Hi All

I want to simulate an ambient vibration to be used as an input to a Numerical Model. I want this to represent the vibrations occurred to the building through the wind, vehicle/human movement, etc.

The sole purpose of simulating this ambient vibration is to input it to the numerical model in order to find out the natural frequencies, mode shapes and damping ratios of the building through Operational Modal Analysis

Thank you