Відео

in FRF plots @4:00 : the vertical axes do not appear to be correct. The Imag axis should be Flipped in the lower phase diagram.

I want to find the damping ratio of a helical spring using this method: 1. Attach an accelerometer at the top of the spring. 2. Disturb the spring by hand to generate a time vs. frequency graph. 3. Convert this time vs. frequency graph to an FFT to see the frequency vs. amplitude graph. 4. Find the damping ratio using the half-bandwidth method on the FFT. My questions are: a. Is this the right method to find the damping ratio, or is the FRF necessary to include the force with hammer impact? b. What if I use or don't use an impact hammer as in this video?

Can you make one video using audacity too? I want psd curve in it

I want to find the damping ratio of a helical spring using this method: 1. Attach an accelerometer at the top of the spring. 2. Disturb the spring by hand to generate a time vs. frequency graph. 3. Convert this time vs. frequency graph to an FFT to see the frequency vs. amplitude graph. 4. Find the damping ratio using the half-bandwidth method on the FFT. My questions are: a. Is this the right method to find the damping ratio, or is the FRF necessary to include the force with hammer impact? b. What if I use or don't use an impact hammer as in this video?

how can I download or buy this software?

Nicely explained. Keep it up.

Can we find the damping ratio of helical spring using harmonic analysis in ansys?

thank you, very good video!

Is neccesary to add an hysteresisi filter if the signal will be filtered with the peak valley method? Or there are signals that might need both procceses as the complexity is higher? Can other filters be added instead of the hysteresis filttering?

sir, how to determine the hours of 1 cycle?

Very informative - thank you!

Thanks for sharing! Very clearly explained the difference between sound power and pressure 👌

Would this still give accurate displacements for impulses in the data? If I drive over multiple small bumps and measure acceleration, would I be able to accurate determine the height of the bump?

as shown at 2:24 from where to get the ductility and strength coefficient and exponents of material if we have to add new material?

Hello, I'd like to ask about the software. I'm using LMS Testlab now. What is the different between Testlab and Testlab Neo? And Is it possible to calculate psychoacoustic tonality in LMS Testlab? Thank you and look forward to your reply

28:34 where have you guys defined the other natural frequencies and whole curve for other systems so, how does this spectrum come without specifying these parameters

How did you define the no. Of systems and their natural frequencies for an example if DUT is a bicycle then : 1. Is all the bicycle component will be counted as different system where SDOF model will be applied to each and every system (bicycle components) and similarly the natural frequency of all those components as well as there SN curve will be u still see to find the FDS curve Are my above assumptions correct or please suggest the correct assumption

14:00 why pseudo velocity is the one to use

Can i use this parameters to compute power (in dB) from a EEG - specific band over time ?

The software can do IIR filter? And mathematic codes?

Nice. What about 30Hz 90Hz 150Hz amplitude and phase response?

Very informative. Lady has a beautiful voice. Thank you.

very good video. Pls how do we calculate the remaining life of a part if given that different loads were applied and different numbers of cycles generated?

how did you decided the length of the hystereis gate?

why is the damping ratio different for all peaks. damping ratio for a material should be same .

How can we save report in word file?

7:08 why?only inner counted?

Thank you!

This is why I do not loan my equipment to others!

Excellent presentation !

Thank you so much. Is there any code for these theories?

Are u from Siemens ?

Are Auto power spectrum and cross power spectrum types of Fourier transform representation

11:30

Hi!! We're doing a modal test using 6061 aluminum shallow plate(15cm x 8cm) . We've attached 12 accelerometers on the plate, and fixed one edge of the plate to the vibration shaker. We're trying to find the 'response characteristics' of three different cases. 1. modal test using only impact hammer 2. random test using only vibration shaker 3. random test using only vibration shaker (condition : the fixed bolts of the vibration shaker is a little bit loosened) can you guess the reason why there are response characteristic differences? plus, do you think there's an algorithm to testify loosened bolts?

grazie bro

Really amazing with good humor. Thanks guys

Great video, really insightful... thank you

Great Video 😊

Finally! A presentation on torsional vibration that helps me visualize the vibration. It's easy to imagine bending frequencies, but not vibration caused by torsional forces. 👍

Thank you so much

Thanks

Thanks, really helped !!

Something that I have noticed is that for an absorption material, there are different applications which might require a different absorption coeffient curve than another material Example. For critical music/speech listening environment, we have a hearing curve which is not a flat curve, and I've noticed that some materials that have an absorption curve that is closer matched to hearing curves that they sound better than other materials for these types of applications. That's why I stay away from building materials like fiberglass (compressed or non-compressed), or mineral wool. Also, open cell foams have different cell structure and density so there are differences in open cell foams too. Another material that isn't discussed is activated carbon, it's highly porous and very dense material, but it comes in typically pellet forms and there's a wide variety of different types of activated carbon on the market. I did notice one company mfg's their own activated carbon and they use it as a fill material inside a pressure based diaphragmatic absorbing products more for the low frequencies down to 30hz. I read a Salford University study on using Activated Carbon for low frequency absorption.

On what basis did you select reference points? Is it possible to somehow do without them?

Is there a sample time series I can use to test my code with?