Physics investigation guidance: Vibration of circular plate

In summary, the conversation is about an investigation into the vibration of a circular plate and its standing waves. The person conducting the experiment is having difficulties interpreting the data and determining the speed of the wave in the plate. They were advised to look into acoustics and bessel functions, and were given a helpful paper as a reference. However, they lack the mathematical background and need someone to guide them in applying their data and understanding the physics behind it. They also mention their teacher's limitations in the topic and seek guidance on the PhysicsForums. The attached file is a photo of six circular nodal patterns from the experiment.
  • #1
alexao1111
4
0
Hi,

I have previously made a post in order to gain some insight in my rather out of control project. Long story short I am investigating vibration of a circular plate and its standing waves. After consultation at this forum I have been guided in the direction of acoustics and bessel functions (which at the moment is a bit more than I can handle but due to the nature of my investigation it's something I just have to deal with).

I can start off with explaining a bit more in-depth of what I have and what I want to achieve. I have conducted an experiment where I have a plate which is connected to a mechanical wave driver and a signal generator. Then after I have sprinkled sand over the plate and changed the frequency until I get circular nodal patterns. My problem now is that I'm having some difficulties how to deal with the information I now have. I have noted down all the frequencies in which these patterns appear, and then measured the diameter of all circles in the pattern and then counted the amount of rings which are present. With my equipment I managed to measure from 1 to 7 rings, where the first one often is immeasurable sometimes because it disappears into the screw at the center of the plate. Now this is what I have, and what I wanted to achieve was to find the speed of the wave in the plate, using the information gathered from the rings. I was told to look into bessel functions and I was referenced to this paper (http://www3.ic.ac.uk/pls/portallive/docs/1/8649699.DOC) which has proven to be quite helpful. Now the actual issue is that I lack the mathematical background, though I have a friend who is willing to help me through this, though the physics part is what is the most troubling. What I really need is someone willing to explain to me how to break it down mathematically. Guide me such that I can properly apply my data, and then sit down with my friend where he can explain the mathematical process to it in terms of solving any potential differential equations.

I basically want to determine the speed of the wave through the plate by using the circular nodal patterns/standing wave patterns of the salt which are formed on the circular plate. Though I am quite unsure how to interpret the data. My teacher is supposed to help me, though it seems like the topic is a bit beyond him as well, therefore I seek guidance at the PhysicsForums. Any help is greatly appreciated, I find the investigation extremely intriguing though a bit intimidating as well due to its advanced nature, I still hope this is something I will be able to pull off.

(The attatched file is a photo from the experiment with six circular nodal patterns)
 

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  • #2
alexao1111 said:
Hi,

I have previously made a post in order to gain some insight in my rather out of control project. Long story short I am investigating vibration of a circular plate and its standing waves. After consultation at this forum I have been guided in the direction of acoustics and bessel functions (which at the moment is a bit more than I can handle but due to the nature of my investigation it's something I just have to deal with).

I can start off with explaining a bit more in-depth of what I have and what I want to achieve. I have conducted an experiment where I have a plate which is connected to a mechanical wave driver and a signal generator. Then after I have sprinkled sand over the plate and changed the frequency until I get circular nodal patterns. My problem now is that I'm having some difficulties how to deal with the information I now have. I have noted down all the frequencies in which these patterns appear, and then measured the diameter of all circles in the pattern and then counted the amount of rings which are present. With my equipment I managed to measure from 1 to 7 rings, where the first one often is immeasurable sometimes because it disappears into the screw at the center of the plate. Now this is what I have, and what I wanted to achieve was to find the speed of the wave in the plate, using the information gathered from the rings. I was told to look into bessel functions and I was referenced to this paper (http://www3.ic.ac.uk/pls/portallive/docs/1/8649699.DOC) which has proven to be quite helpful. Now the actual issue is that I lack the mathematical background, though I have a friend who is willing to help me through this, though the physics part is what is the most troubling. What I really need is someone willing to explain to me how to break it down mathematically. Guide me such that I can properly apply my data, and then sit down with my friend where he can explain the mathematical process to it in terms of solving any potential differential equations.

I basically want to determine the speed of the wave through the plate by using the circular nodal patterns/standing wave patterns of the salt which are formed on the circular plate. Though I am quite unsure how to interpret the data. My teacher is supposed to help me, though it seems like the topic is a bit beyond him as well, therefore I seek guidance at the PhysicsForums. Any help is greatly appreciated, I find the investigation extremely intriguing though a bit intimidating as well due to its advanced nature, I still hope this is something I will be able to pull off.

(The attatched file is a photo from the experiment with six circular nodal patterns)

Rossing and Fletcher. http://books.google.com/books?id=SgBF0j2OfKMC&pg=PA73#v=onepage&q&f=false
Discuss vibrations in circular plates.
Look at Eqns. 3.11, etc.
Table 3.2
Figure 3.8
 

1. What is the purpose of investigating the vibration of circular plates in physics?

The purpose of investigating the vibration of circular plates in physics is to understand the behavior and properties of these structures under different conditions. This can help in designing and engineering various systems that involve circular plates, such as musical instruments, turbine blades, and heat exchangers.

2. What factors affect the vibration of a circular plate?

The vibration of a circular plate is affected by factors such as its size, shape, material, boundary conditions, and excitation source. Other factors, such as temperature, humidity, and external forces, can also have an impact on the plate's vibration.

3. How is the vibration of a circular plate measured and analyzed?

The vibration of a circular plate can be measured using sensors such as accelerometers, strain gauges, and laser vibrometers. The data collected from these sensors can then be analyzed using mathematical techniques such as Fourier transform and modal analysis to determine the modes of vibration and other characteristics of the plate.

4. What are the different types of vibration modes in circular plates?

The different types of vibration modes in circular plates include radial, circumferential, and bending modes. Radial modes involve motion along the radius of the plate, circumferential modes involve motion around the circumference, and bending modes involve flexural motion of the plate.

5. How can the vibration of circular plates be controlled or minimized?

The vibration of circular plates can be controlled or minimized by adjusting the boundary conditions, changing the material or thickness of the plate, using damping materials, or applying external forces. Careful design and engineering can also help in reducing unwanted vibrations in circular plates.

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