Hello
I have a central body held by 4 blades stretched with screws. I would like to simulate the vibrations, but to be consistent you need the tensions in the blades, and I don't know how to do it on my simplified model because the end of the blades is in contact with the support.
In reality:
And modeled simpler for the frequency study:
Hello
You have to use the premium professional simulation version to be able to do a good frequency study
You can do it on a quarter of the model, it's enough, so you only have one blade to observe. You have to do your simulation with the real blade with holes otherwise you won't get the same result as with a blade without a recess.
I don't know if it's the whole assembly or only the top crown that holds the blades. To be specified!
On the other hand, if I may allow myself a friendly remark, your blade will not be in tension with a rig as you present it on the drawing at the top. In addition, putting all your blades vertically is not the best way to limit the increase in vibration beyond a certain frequency. But hey, that's not in the question so I didn't say anything :-) :-)
Kind regards
Thank you for the answer, but my problem is how to tension the blade?
You simply have to simulate a quarter model using the perforated blade to obtain a good result (concentration of stresses), considering that the blade is recessed on one end only, is a tensile force of the other end.
Good luck
Kind regards.
Hello, why not just isolate your blade to do your simulations???
As a result, you will quickly see in which direction it resists the most, and the model being lighter, the calculations will be faster!
Cdt
G.
The problem is not the resistance of the blade, the telescope already exists and it works well. I look for the natural frequencies of an entire system to refine a servo that is disturbed by a resonance, so I need to know the frequencies better for the trips in the servo.
As much as for me, I hadn't seen the problem in that sense:)
However, if you stiffen your parts, you should reduce or even eliminate the resonance! No???
Absolutely, but for now I have the natural frequencies, but without tension on the blades, so not good. I would like to see how much I have to stretch the blades to go up to 80 to 100Hz, which will allow me to neglect this frequency.
I did a test with just a frame and the central body, but it doesn't work. I put the counters at the end of the blades, but obviously no contact is made between the boards and the frame. Here's what I have:
In simulation it is possible to put bolts (in connections you choose 'bolts').
If you want a coherent result, you have to model your part with the same connections as in real life and in your case with the real masses (so the holes in your blades....).
You have to drill your frame and put a bolted connection between your frame and your blade.
You can put a prestressing force in your bolt (or a torque).
If you follow our advice you should get something correct
I did find the bolt type connection, but it's only in static studies, it doesn't exist in frequency studies, or I missed something.