Have no idea of the source I was just provided the YouTube link (click on the YouTube logo to go there) from Tony. I did some searching but came up with nothing… If you find something please post it here.
For what it’s worth, what’s being shown are modal vibration patterns, called Chladni patterns (the name always put me in mind of Klodni from the Rocky & Bulwinkle martian pair). They’re heavilly used in instrument making, especially violin family instruments: the luthier shakes sand onto a wood plate which he is carving, and bows the edge with a standard bow. It requires experience to know how hard and fast to bow, but they can excite the modes they want to see very easily, and the sand gathers in the nodes (the parts that don’t move in the standing modal wave), outlining the areas that do move.
The same effect can be gotten using holography, for which some video systems exist (pcholo.com). These are used to verify mechanical systems, and often can separate very close vibration modes, allowing modifications to reduce metal fatigue, etc. The computer design equivalent is finite element analysis.
The source is A.) a frequency generator, which is fed through a B.) audio amplifier, that is connected to C.) a cool little device called a “Soundpad” which you can attach to any thin, flexible board to make a speaker. Here’s the link:
May 30th, 2006
source?
May 31st, 2006
Have no idea of the source I was just provided the YouTube link (click on the YouTube logo to go there) from Tony. I did some searching but came up with nothing… If you find something please post it here.
May 31st, 2006
For what it’s worth, what’s being shown are modal vibration patterns, called Chladni patterns (the name always put me in mind of Klodni from the Rocky & Bulwinkle martian pair). They’re heavilly used in instrument making, especially violin family instruments: the luthier shakes sand onto a wood plate which he is carving, and bows the edge with a standard bow. It requires experience to know how hard and fast to bow, but they can excite the modes they want to see very easily, and the sand gathers in the nodes (the parts that don’t move in the standing modal wave), outlining the areas that do move.
The same effect can be gotten using holography, for which some video systems exist (pcholo.com). These are used to verify mechanical systems, and often can separate very close vibration modes, allowing modifications to reduce metal fatigue, etc. The computer design equivalent is finite element analysis.
May 31st, 2006
The source is A.) a frequency generator, which is fed through a B.) audio amplifier, that is connected to C.) a cool little device called a “Soundpad” which you can attach to any thin, flexible board to make a speaker. Here’s the link:
http://www.si-technologies.com/frontEnd/cm_productDetail.jsp?productID=23
May 31st, 2006
Thanks for the info Ray and Mark
Here is a link based on Ray’s info:
http://www.physics.utoronto.ca/nonlinear/chladni.html