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Lower-bound knockdown factor

Lower-bound knockdown factor

Lower-bound knockdown factor

(OP)
Hello, can anyone shed a light on what a lower-bound knockdown factor is (in context of structural design)? (or an "upper-bound factor" for that matter)

RE: Lower-bound knockdown factor

Not a standard term that I've heard.

Closest thing that comes to mind is a push-over analysis.

Can you provide some more context?

----
The name is a long story -- just call me Lo.

RE: Lower-bound knockdown factor

Are you thinking 'shakedown' factor for plastic design?

Dik

RE: Lower-bound knockdown factor

Knocking down a structure? or rounding up reactions? Fatigue?

RE: Lower-bound knockdown factor

composites maybe (environmental and process knock-down factor ?)

another day in paradise, or is paradise one day closer ?

RE: Lower-bound knockdown factor

Think I've seen that term some place before, certainly not a common usage, though. But the context fits this internet quote: "Shell-buckling knockdown factors (SBKF) have been used in large cylindrical shell structures to account for uncertainty in buckling loads. As the diameter of the cylinder increases, achieving the manufacturing tolerances becomes increasingly more difficult. Knockdown factors account for manufacturing imperfections in the shell geometry by decreasing the allowable buckling load of the cylinder..."

IE, it doesn't relate to knocking anything over or down, more like a safety factor, etc.

RE: Lower-bound knockdown factor

Quote:

Think I've seen that term some place before, certainly not a common usage, though. But the context fits this internet quote: "Shell-buckling knockdown factors (SBKF) have been used in large cylindrical shell structures to account for uncertainty in buckling loads. As the diameter of the cylinder increases, achieving the manufacturing tolerances becomes increasingly more difficult. Knockdown factors account for manufacturing imperfections in the shell geometry by decreasing the allowable buckling load of the cylinder..."

Yes, I've seen it called that in texts on buckling of shells as well. And if that is what he is getting at.....that number can really vary based on geometry, loading, etc. It needs to come from code (like ASME). Initial imperfections can be a killer for shell buckling.

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