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Thermal stresses on capacitor.
Posted 13 ago 2014, 04:20 GMT-4 Heat Transfer & Phase Change, Structural Mechanics Version 4.3b 0 Replies
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I'd like to ask your help in a model of a capacitor that I am trying to build, on a PCB board (ver 4.3b). I have designed the capacitor with the Ni electrodes and the dielectric ceramic material. I have designed the PCB board, on top of which the capacitor is placed. I want to see the thermal stresses under 120 degrees Temperature, where the capacitor with the PCB are put inside an 'oven' and the heat is tranfered through the air. Thereby, my question is, which boundbary condition is the best:
1. Use the 'Temperature 1' condition and apply the 120 degreees to all surface?
2. Use the heat flux condition, with the heat transfer coefficient ot air around 5-10?
3. Use another method?
My problem is that I have used the first two conditions and I have found von Misses stresses in the magnitude of 10e14!! But according to physics, the yield strength of my Ni electrodes it around 140 MPa!!!
I try to use the v.M.stresses for the failure criterion that the material failures when the v.M.stess exceeds the yiled strength, but I have a v.M.stress in the magnitude of teraPascal and the yield strength, of MPa!
Do you have any idea, what may be wrong and how can I reduce the v.M.stress of my capacitor to reasonable values?
Thank you alot beforehand.
Best regards
Hello
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