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Exploding wire fragments
Posted by Joe Perkins on 3/2/2004, 11:07 pm I think I have an explanation for the mysterious effects noticed in the copper wire fragments in the magnetoforming experiments. Copper wire is formed by extrusion through a die (as is most wire) and this places a lot of stress on the crystalline structure. The dies used can introduce a fold in the metal as it's formed that are not apparent in the final piece of wire.. a real problem sometimes as this can weaken the wire. The shattering is purely breaks at the crystalline boundaries of the wire and occur during really high speed shock. The folds in the wire are the folds introduced during wire forming that have "unravelled", so to speak. That takes one hell of a lot of mechanical power and speed to do.. neat trick Me, I just love testing extremely high voltage power interrupters on 384KV multimegawatt power grids.. something about that deep throated hum and 30 foot arcs like gigantically insane Jacobs ladders
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Re: Exploding wire fragments
Posted by Bert Hickman on 3/3/2004, 1:02 pm, in reply to "Exploding wire fragments" Hello Joe, Thanks for your idea regarding wire fragmentation. Fragmentation seems to occur with not only copper wire, but also with wire made from other metals. To the extent that similar internal folding may deveop during the wire drawing operation for other materials, perhaps yours is indeed a possible explanation. The current "official" thinking seems to be that flexural vibrations are set up within the wire, causing periodic tensile forces that then tear the wire apart. However, there really doesn't seem to be a single explanation that squares up with all of the various observations. It sounds like you have a very interesting job - it's great when you can get paid for having fun! If you ever happen to capture some "interesting" still shots or videos, I would be very interested in receiving copies to share in the Arcs and Sparks section of my site. Thanks again and best regards, -- Bert --
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