Quote:
Originally Posted by SteveS
I have built both, but prefer parabolic bracing, make that parabolic lattice bracing. The term parabolic is applied in a general sense to indicate that the transition in height is very gradual, but there is no way any one's braces are actually parabolic.
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As Steve says, no one actually shapes braces to a parabolic curve. When I first heard the term, I asked the person using it (who I believe originated the usage) if he knew the quadratic equations for the parabolas he used. He ignored the question. I have never seen or heard of anyone who plotted a parabola and used it as a model for a brace. Conclusion: "parabolic" is just puffery; a misleading term that is being used to imply a scientific knowledge and geometric precision that does not exist. All it means in connection with bracing is 'convex.'
Scalloping is not intended to be a way of maximizing structural strength or rigidity with a minimum of mass, which is probably what the OP's engineer friend was assuming. It is a way of shaping tone by introducing a tendency toward certain nodes and antinodes in the modes of top vibration. How it does this is a matter on which there is disagreement, and which could be the subject of a lengthy treatise.