To learn more, please read our Privacy Policy. By choosing I Accept , you consent to our use of cookies and other tracking technologies. I Accept. Price Up to Total Studio 3. Choose your Total Studio 3. For example, the selected position is Hz, a number of bands are 1, and Delta frequency is We can see that the central position is at Hz and we have one band in each direction. So the line on the left side is at Hz and the line on the right side is at Hz.
Distance between the lines can be defined by the user, in our example, it was Hz. The harmonic marker can be enabled at any frequency. The harmonic marker will mark the harmonics of the selected frequency. The base marker of the harmonic marker can be selected and moved to any other frequency with the harmonics updated live.
Monitoring harmonics is very important in the order tracking analysis. An example was made with a blue toy in the picture below accelerometer was attached to the machine.
We run the machine to RPMs and measure vibrations in the process. Move the mouse to the FFT graph and select the icon for a Harmonic marker. Then select the base frequency with the mouse and add a harmonic marker with the click on the left button. If we select the Number of harmonics as 3, we will see lines at And the theoretical harmonics also nicely match our measurement results - the first three harmonics are nicely seen. You can also pick and drag the fundamental frequency through the FFT spectrum.
Harmonics will automatically follow. Damping markers are best to use in modal testing when we want to find out how our transfer curve is damped. We select it when we are interested in the quality factor, damping ration, or attenuation rate of a selected peak. Move the mouse to the FFT graph and select the icon for the Damping marker. Then click on the mouse button to the position, where you want to add a damping marker.
In the picture below we can see a transfer curve of a beam. On each of the peak, we attach a damping factor and in the marker table we can see the quality factor Q , which tells us, how much the transfer curve is damped.
If the Damping factor type is chosen as Attenuation, the result is the attenuation ratio for each peak. Each bearing database includes bearing data what is the base of component cage, rolling element, outer race, and inner race at 1 Hz and at which frequency has the component a peak in the frequency domain.
In the Kinematic cursor editor, add a new bearing or select from the existing database, selecting the Append bearing option. Channel calculated with Envelope detection math must be now set as the input channel to the FFT analyzer. Now we can see bearing cursors at frequencies that are defined is bearing database. The table shows to which mechanical part the frequency is related.
The higher the FFT lines value, the better the resolution. This line resolution depends on the sampling rate and the number of lines chosen for the FFT. If our peak falls between frequency lines, the frequency will not be exact. Because harmonics are multipliers of the fundamental frequency, the error will increase at every higher harmonic. If we mark the interpolate peak options, our markers will be interpolated in frequency and in amplitude!
Newest courses. Table of contents. What is frequency analysis? The time period T is the duration of one cycle and is the reciprocal of the frequency f : What is frequency analysis? We can also say that frequency analysis checks the presence of certain fixed frequencies. Image 1: Signal consisting of three sine waves with different frequencies.
Image 2: Frequency representation of sine waves with different frequencies. Fourier transform. Fourier series Any periodic waveform can be decomposed into a series of sine and cosine waves: where a0, an, and bn are Fourier coefficients: , , Discrete Fourier transform For discrete data, the computational basis of spectral analysis is the discrete Fourier transform DFT.
Image 3: Square wave displayed in time above and in the frequency domain below. Image 4: An example of successful and unsuccessful extraction of frequency. Let x0, We have already seen that DFT is defined by the formula: Evaluating this definition directly requires N2 operations: there are N outputs of Xk, and each output requires a sum of N terms. Image 5: Time and frequency representation of a square wave signal.
Properties of Fourier transform. Image 6: Typical FFT screen. Number of lines Line resolution [Hz] Calculation time [s] 21,5 0, 10,75 0, 2, 0, 0,67 1, Image 7: FFT results displayed on a linear scale. Image 8: FFT results displayed on a logarithmic scale. Image 9: Linear frequency scale. Image Logarithmic frequency scale. Windowing functions. Image Leakage from a sinusoid. Image Spectrum display without spectral leakage Image Small frequency peak obscured as a result of leakage Image Adjacent peak spectrum display with windowing, smaller frequency peak is no longer obscured.
Image Characterisation of windowing functions. Fourier transformation errors. Amplitude error picket-fence effect The sum can produce "non-null' results even when the signal does not correspond to the frequencies extracted from the signal. Image Amplitude error and leakage of the FFT result no window.
Image Windowing functions in time domain. Image Hanning window left and Flat top window right. Image Window properties description. Image Zoomed FFT of a pure sine wave. Image Aliasing effect in the time domain Of course, the problem above is not an FFT problem, but it is very important to know how to correctly identify the cause of the error. Averaging of the signal. Image Graphical representation of overlap function. Representation of different signals in the FFT. Triangle, rectangular On the left side, in the picture below we can see a Triangle signal in the time domain and on the right side is the Triangle signal in the frequency domain.
Image Triangle signal in time and in the frequency domain. Image Rectangular square signal in time and in the frequency domain. Image Impulse signal in time and in the frequency domain.
Image White noise signal in time and in the frequency domain. Image Beating signal in time and in the frequency domain. Image Amplitude modulated signal in time and in the frequency domain. FFT analysis module in Dewesoft. Image FFT analysis module setup in Dewesoft. Image Amplitude and Complex output channels. Image Different possibilities for calculation type. Image Setting the windowing function and line resolution. Image Block history calculation - FFT is calculated for each block of data individually.
Image Averaging of data blocks. Image FFT is averaged from 2 blocks of data. Image Overall Averaged calculation type. Image Windowing functions. Image Resolution settings. Image Amplitude scaling. Image DC cutoff options. Image Overlap selection. Image Weighting curves. Image Averaging type. Image Adding FFT preview. Image FFT visual control in Dewesoft. Example of measurement with FFT analyser. Image FFT analysis setup. Image Adding a new 3D graph widget.
Image Different option from projection on 3D graph. This map roughly quantifies the quality of focus for each pixel point in the chosen rendering region by computing the effective "Numerical Aperture", defined as sine of half of the angle between the first and last beams covering the pixel.
The concept of numerical aperture comes from microscopy and represents the angular coverage of a focal point. A low numerical aperture value implies that energy is not effectively focused at a particular point leading to poor resolution and low image intensity, whereas a high numerical aperture value means that energy is highly focused leading to high resolution and high image intensity.
View and scroll through the data either as is, or folded along the soundpath. Apply an Alpha Threshold to the data to remove noise and low amplitude signals. BeamTool now helps you to select the correct range of angles for Phased Array inspections by displaying the energy associated with each beam defined within a beamset. Low energy beams will be difficult to calibrate and require a large amount of gain to be properly normalized.
The calculated energies take into account the directivity of the probe elements, the transmission coefficient between the wedge and the piece, as well as the reflection coefficients for each skip within the piece.
For multi-beam beamsets, you can highlight a single beam and also view its focal law delays. Weld region parameters can be separately configured for the left and right side of the weld bevel. A clad layer can now be added to a plate, T, axial or circumferential piece configuration. BeamTool now supports the rotation of probes around the vertical axis.
When both compression and shear paths are displayed, you can now color each sound mode independently. The Linear Spread beamset now supports Compound-S mode which allows specifying the angle step between each successive beam. The weld can now be a different material than the rest of the piece. For the sound paths to be affected by the alternate material, "Reflect off Weld" must be chosen in the Beamset configuration.
The backing bar can be inset, and is now available for Axial pieces. This can help when the various sound modes become too cluttered. When the transverse angle is not zero, beamset measurements can be calculated from multiple points of view view planes. BeamTool was designed to meet the modern operator's need for speed. Phased array technique development is more complex than that for conventional ultrasonic inspection and as such requires effective tools to help define the inspection approach.
BeamTool's innovative approach to phased array enables linear, sectorial and an informative reference cursor option to be represented, helping to clearly convey weld coverage, HAZ coverage and probe position, in addition to critical dimensions. Z Amps, Inc. All other product names and images, trademarks and artists names are the property of their respective owners, which are in no way associated or affiliated with IK Multimedia.
Use of these names does not imply any cooperation or endorsement. Mac and the Mac logo are trademarks of Apple Computer, Inc. We use cookies and other tracking technologies to improve your browsing experience on our site, show personalized content and targeted ads, analyze site traffic, and understand where our audience is coming from.
To find out more or to opt-out, please read our Cookie Policy. To learn more, please read our Privacy Policy. By choosing I Accept , you consent to our use of cookies and other tracking technologies. I Accept. AmpliTube 5 Custom Shop Hot-rod your desktop. AmpliTube 5 Custom Shop. Key Features. AmpliTube 5 versions. AmpliTube 5 SE.
0コメント