Sam Davies
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 Feb 1 awarded Yearling Nov 15 awarded Popular Question May 22 awarded Nice Question Nov 16 awarded Yearling Jul 24 awarded Nice Answer Jun 19 awarded Nice Answer Nov 16 awarded Yearling Apr 18 comment How far does a trampoline vertically deform based on the mass of the object? I don't think a small angle approximation is valid for a trampoline. E.g. a typical circular garden trampoline has height ~R; so a heavy bounce would dip at least R/2 -> 30 degrees. Apr 18 comment Basic explosion physics - determining force Just a quick note re angles - there's nothing wrong with the angle being negative. sin & cos are defined for any angle from $-\inf$ to $+\inf$, with a period of 360 degrees (or 2pi radians). Mar 31 comment Calculate stainless steel pole necking limit ... [cont]: If you're interested in this kind of thing, there's plenty more to read on the internet. E.g. the Singapore tunnel collapse from a few years ago was caused in part because a certain detail was changed by the contractor without properly considering stability (buckling), and this subsequently failed. scribd.com/doc/6231559/DESIGN-AND-FAILURE-OF-SINGAPORE-TUNNEL Mar 31 comment Calculate stainless steel pole necking limit @Anna: Sorry for the late reply. The Wikipedia page on buckling is a reasonable introduction. Or a degree in structural engineering ;-). The main point I meant to get at is that for a complex setup like this, it's important to consider every failure mode. It's rare to find a real-world scenario that requires a simple stress calculation. Sadly also most buckling calculations are very complex (except for very simple structures) so it's not normally possible to calculate for them directly in a situation such as this. ... Mar 10 revised Calculate stainless steel pole necking limit Update: bracket is a weak point too. Mar 10 comment Calculate stainless steel pole necking limit @ Dave: (without knowing the full details of the joint) - I think the weakest point in the system won't be the joint between the arm and bracket, but between the bracket and pole. Clearly the arm is designed to be bolted to the wall, so whatever bolts would be used for that must be strong enough to make the equivalent join to the bracket. Assuming the holes in the bracket are same / similar distance apart as those in the bracket - if they're significantly closer together the forces will be larger. Mar 9 comment Calculate stainless steel pole necking limit Down-voting for the concerns Georg raises in comments to his answer. There's no explanation (or reason as far as I can see) to go from $strain = stress/Young modulus$ to $r = pressure rating / m.g$. The answer makes no mention of buckling and doesn't look at how the arm is attached to the pole. Mar 9 awarded Critic Mar 9 answered Calculate stainless steel pole necking limit Jan 12 answered “Magnetic mnemonics” Dec 22 answered Why does measured pressure change over time in closed hose with temperature gradient Dec 21 answered Simple three-body-problem? Dec 11 awarded Quorum