>>I see. Maybe you can expand on that. What I'm picturing is the >>curved bridge with string load which overloads the board in that >>section of the bridge with the most severe curvature. The bridge >>is being pushed down in that area, but is still being supported at >>its ends, so as it is being pushed down it has no choice but to >>twist (roll). Am I picturing this the way that you would? > >Yes you are, but I don't see how the proportional split of front to >back bearing will make any difference here. If the soundboard hadn't >failed to hold the bridge up at the curve (killer octave), it >wouldn't have "rolled". >... >Ron N Faulty reasoning on my part I think. I had been thinking of the bridge cross section with loads applied to it and with reactions occurring at the cross section CG. If you look at it that way, then having different load magnitudes at the front and back faces of the cross section, with their attendant moment arms from the CG, would cause a rolling moment about the CG, as well as a downward load at the CG. That sounds OK in theory. However, on a real bridge, the reaction really isn't just at the CG, but along the entire bottom of the bridge. Load applied at the front face will probably go straight down and be reacted by the ribs, and the same with the load on the back face, so there would be no tendency to roll the bridge just from those loads. Phil Ford
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