Controlling a chain of masses to vibrate at a certain signal

Projects General Guidance
1

Hello,

I'm a graduate student trying to design an experiment.

My adviser and I have come up with a model as to how an infinite chain of masses connected by nonlinear springs should vibrate without forcing, i.e. free wave propagation in the chain. We would like to experimentally verify this model.

Assuming I can fabricate the chain (many masses connected by springs with some nonlinear element such as magnets in between each of them), I was wondering how I could test if our theoretical wave would be supported by the chain.

What I had in mind was this: have each mass initially connected to some kind of wheeled object (small cart type thing) that is controlled by an Arduino to oscillate at our theoretical signal. Then, very slowly, the connection to each mass by its respective cart would be removed. We would then know if our model for free vibration is correct if the wave continues to propagate in the chain unaltered, i.e. we could measure the same signal.

Because our chain is theoretically infinite in extent, we would have to restrict our measurements to a central portion so that reflection at the boundaries wouldn't kick in yet. I would probably measure the velocity of masses using Laser Doppler Vibrometers.

How feasible is this idea? Can I use Arduino controllers on each cart to give them the right signal? What could I use to slowly remove the connection between each cart and mass in the chain? A slowly retracting solenoid? Could I program an Arduino to do that?

Any other suggestions are welcomed!

Also, I'm brand new to Arduino: I do not have any of its products nor do I have any experience using its products.

Thanks!

Matt

2

What's the budget, $100, $1k, $10k?.
How many masses need to be moved?
How much do they each weigh?
How precise does the oscillation need to be in terms or absolute period and unwanted harmonics of the fundamental?

Stepper motor systems will add unwanted step harmonics.
Servo system will add unwanted harmonics due to imperfections in the control loop.

3

Rather than pose the question about a large number of masses, the first thing you should do is figure out exactly how you might use an Arduino to cause a single mass to do what you want.

That means designing (at a sufficient level of detail) the mechanical system that you have in mind. Then you will be able to tell us (ideally with a diagram) exactly what you want the Arduino to do.

Only after that will it make sense to consider multiple masses.

...R