Ron Nossaman wrote: > > Panel compression psi necessary to produce given deflection - how much > unloaded crown > P is obtained with above equation > Pc = ((P*(Lin/2))/((H+Pt)/2))/(Pt*Pw) > > Any corrections, comments, or additions so far? Ron, This looks familiar. Isn't this the same as the formula I sent you a few years back. I have lost the file this was on but if I remember I was trying to figure panel compression using simple moments of force. I wasn't feeling confident that this approach would work so I have since abandoned it. If you can get this to work and can explain it to others the more power to you. To be fair you should use a pine rib, this is what Steinway uses on there panel crowned boards. You also need to scallop the ends of the ribs and cove the bottom. All of this will effect panel compression. I think a direct approach will be more conclusive. Make two cross grain strips of soundboard panel the same length at the same EMC. dry them both down to 4.5%. Glue a rib on to one of them using a flat surface. Let both samples reach EMC with the environment, say 40% RH. Check the level of crown and compare the length of the strip with the rib to the other strip. The difference in length will give you the compression. John Hartman RPT John Hartman Pianos [link redacted at request of site owner - Jul 25, 2015] Rebuilding Steinway and Mason & Hamlin Grand Pianos Since 1979 Piano Technicians Journal Journal Illustrator/Contributing Editor [link redacted at request of site owner - Jul 25, 2015]
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