creating a vibrating component

[lucy_33]

hello!

trying to create a component that moves back and forth at a high frequency, with the part moving back and forth a specified amount.

could anyone recommend a technique or approach with which to accomplish this? feeling stuck.

thanks in advance!

 

[onatirec]

Do you have some more information on frequency, force, and displacement?

Linear resonant actuators are the first thing to come to my mind, but the ones I've seen are small (haptic feedback) motors.

 

[lucy_33]

it's a component that's ultrasonically powered, so looking at a frequency of around 50kHz and a displacement of ~150um

 

[drawoh]

lucy_33,

What year are you in? Vibrations is normally third year mechanical engineering, after you have done quite a bit of mechanics of materials, and differential equations. If you do not have this, you are in over your head.

This is a fairly manageable vibrations problem.

--
JHG

 

[IRstuff]

https://www.hindawi.com/journals/sv/2020/9834324/

Ultimately, it boils down to having a piezo transducer that can move that much, assuming sufficient voltage and/or power

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

https://www.youtube.com/watch?v=BKorP55Aqvg

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[lucy_33]

I'm a graduate biomedical engineering student, and this is my first time using an FEA tool. I'm attempting it as a part of my research project.
Since I'm not familiar with the software, I'm not sure what types of tools would be useful for creating this type of simulation. So you're right, I may be over my head, but I'm determined and need to figure it out anyway

 

[lucy_33]

(for reference, I'm trying to use ABAQUS! can't believe I forgot to put it in the original post, but thank you for all of the feedback so far!)

 

[drawoh]

lucy_33,

How much mechanical engineering training to you have?

You are designing a reciprocating device. The forces needed to reciprocate something are massively affected by the size, mass, amplitude and frequency. This is all fairly easily worked out by Newtonian physics. Here is some quick and dirty math, assuming you are doing a sine curve...

Displacement [—] x(t) = X sin [ω]t
Velocity [—] v(t) = [ω]X cos [ω]t
Acceleration [—] a(t) = -[ω]²X sin [ω]t
​

X is your displacement amplitude.

[ω] is your circular frequency, where [ω] = 2[π]f.

If you plan to operate your device at some resonant frequency, you need to understand all the nasty math behind vibrations, as well as the mechanics of materials. Think about spring rates and metal fatigue.

FEA is not a substitute for understanding the engineering. The very nasty differential equations can be solved numerically.

--
JHG

 

[lucy_33]

JHD-

Respectfully, I am able to do the math behind this problem. As I also got my undergrad degree in biomedical engineering, I have taken mechanics, differential equations, and ultrasonics courses.

-

I think my question is more how creating these types of devices works in a software such as abaqus. Like, is it something that should be set as a load? as a specific type of step? as a property? multiple of the aforementioned?

 

[drawoh]

lucy_33,

Sorry. I am not familiar with biomedical engineering, so I asked. I am not familiar with Abaqus either. If this were my problem, I would be using SolidWorks Simulation.

A big problem with CAD, particularly simulation programs, is that people operate the tool rather than solve the problem. You need to come up with a design concept. From this, you can identify engineering problems, and you can ask questions which can be answered by some form of engineering analysis like Abaqus. I have a handbook here with tables showing the vibration modes of various simple structures including cantilever beams and flat plates. There is always the square root of k/m.

I am sure Abaqus requires a model of some sort.

Design something. Design even with computers, is an iterative process. Your first idea probably is wrong, but you won't know until you write it out and then analyse it.

--
JHG

 

[lucy_33]

That you for the inspirational words JHG!