I would like to know the answer of a dynamic system. It is a metal strip plated on a flat, slightly domed surface, to which I apply an imposed displacement on the face of its thickness (see photo).
I tried the 4 types of dynamic simulation: Modal versus time / Harmonics / Random vibrations / Spectral response analysis
- For Modal as a function of time: I get a result with the imposed displacement. The speed is chosen as the initial condition.
- For Harmonic: I get an error message "The defined curves are not correct"? Quezko?
I replace this imposed displacement with a force applied at the same place and this time I get a result.
- For Random vibrations: Same error message "The defined curves are not correct". I apply force and I also get a result.
- For Spectral response: Error message ''No base spectrum curves are defined'' whether for a displacement or a force.
I don't really know what to choose among these simulations and I think I have a hard time interpreting the results. I'd like to see if the system remains linear as a function of time but also of frequencies
--> Which simulation would correspond and how to best set it up? (Unfortunately my pc is not a racing beast!)
--> Once the calculation is complete, which plots should I display?
This slat can operate: between 0 and 1000hz / with an imposed displacement of 0.12 mm / alloy steel as material. For the speed (initial condition), I took a somewhat random value because this 0.12 mm displacement is almost instantaneous.
Are you looking for the answer to what request exactly? the frequency of 0-1000Hz applies to the imposed displacement of 0.12 mm? In other words, does the domed part play the role of a spring? Or do you compress the blade and then you look for the natural frequencies of the blade in this position?
In the first case, it seems to me that you are missing the ground at the end of the blade.
I've already read a lot of points about the Solidworks help but between the simulation errors and the interpretations of the graphs, I struggle a little :( . I preferred to make a summary of what happens on each simulation so that you can give me your point of view.
To answer you Chamade, the frequency of 0 / 1000hz applies to the lamella, the latter effectively playing the role of a spring. I would like to know how the lamella behaves in this frequency range. I've already been told about adding a mass, but is it mandatory to get a result?
I already know how to find the resonant frequency but this study will be done later.
Based on this data, which simulation would be the easiest to set up?
I'm not a specialist in the matter but, once again, the type of analysis depends on what you want to know as a result and not on its simplicity.
Do you want a transfer function? Movement at one point? The constraints?
A modal analysis won't give you more than the resonant frequency. In this case, the mass is mandatory because otherwise the result will be wrong. You will have the natural frequency of the blade but not of the system.
I would like to find the transfer function of my lamella with as input data, a displacement imposed according to a frequency. That's exactly what I'm looking for!
For everything related to resonance frequency, displacements or constraints, I don't have a problem with that. I did a simulation with an added mass without any problem.
So it would be more of a spectral analysis. The masses must still be correct because it seems to me that spectral analyses start with a modal calculation phase.
In absolute terms, you must have a low-pass filter response (transmissibility = 1 before the natural frequency, amplification at f=f0 and then attenuation).
I don't have the tool so I won't be able to tell you more about the procedure.
I just did the spectral analysis. I applied my embedding / plane supports / imposed displacement as before, all with a uniform excitation of the base (It is mandatory to use it to have a result).
But on the one hand, the only "excitement" I want is that of my imposed displacement, why add this uniform excitation of the base?? I have no idea what value this trip should be given
You will find attached the screenshot of the simulation.
Without having the tool, I may say anything but, if I understand correctly what is written in the help, you should not use the uniform excitation option but "excitation of the selected base" and choose the imposed displacement of 0.12 mm.
I have already tried this technique but without much success. Once in the "excitation of the selected base" function, I have to choose a fixed geometry in the place where to apply it (plane support / embedded). So I create a plane press on the thickness, I choose it in the function and then launch the analysis.
Here is the result I get, whether it is a linear or curved excitation, with a large or small displacement, by removing the maximum of fixed geometry (see attachment).
Sorry but not having the tool I can't really tell you more.
In a dynamic response analysis, it seems to me that we must indeed choose a "blocking" point of the structure (considered fixed in the preliminary modal analysis that the software performs on its own in the background) that we will use to apply the spectrum of depacement (or acceleration) as a function of frequency.
So the approach seems logical to me. but how to make SW understand, I don't know.