Sam Davies

584 reputation

210

bio	website
	location
	age
visits	member for	2 years, 6 months
	seen	Aug 3 '11 at 15:46
stats	profile views	18

	584 reputation	bio	website		visits	member for	2 years, 6 months
210 badges		location			seen	Aug 3 '11 at 15:46

summary answers questions tags badges favorites bounties reputation activity

36 Actions

suggestions reviews revisions comments badges posts accepts all

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
Dec 6	answered	Why does the mass of an object increase when its speed approaches that of light?
Nov 25	answered	Doppler's effect use
Nov 19	comment	Imagine a long bar floating in space. What force does it exert on itself in the middle due to gravity? You're right - thanks. I've corrected this in the original question now.