>You are absolutely correct Ron ....... if you assume that the entire >soundboard assembly is constrained from expanding as it takes crown. Such >is not the case. If the assembly did not expand, then the ribs would be >under NO tension and would be incapable of opposing the load exerted by the >soundboard. If the ribs are under tension, they stretch, ergo the assembly >does expand. Whether the entire panel is compressed depends on the relative >sizes, geometry, and material properties of all components of the entire >assembly. > >Frank Weston > So what? In a CC assembly, the ONLY reason it takes crown is that the panel is constrained from expanding, on one side, by the ribs. Why would I not assume constraint with panel expansion? Are the laws of physics going to suddenly change arbitrarily? It's inevitable, unless the assembly is kept at the drydown EMC forever, or not dried down at all, in which case you won't get crown, or a working soundboard. Yea, obvious, and so what? I don't see where pounding a point that's contrary to the way it's done, and won't produce a working soundboard is going to get anyone anywhere. In a real world situation, where the intent is to make a nominally functional soundboard by the compression crowning process, the entire panel will be under compression when the assembly is completed and brought to ambient EMC. If you are talking about alternate realities, and soundboard assemblies that are built with no intention of producing a working soundboard, I wish you would say that up front and save everyone some time. I, at least, was attempting to seriously discuss practical concerns and real world phenomena. Ron N
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