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Noisy Rhysling
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Reposted to help a guy out...
Specifications for elephant-resistant steel poles http://www.skepticforum.com/viewtopic.php?p=584279#p584279by Williamhdc » Tue Jun 20, 2017 5:17 am
This is probably simple for an engineer, but I’m a zoologist and analytical chemist and so I would rather ask those who know. I have camera traps out on the African bush, that are monitoring the responses of leopards to artificial scents. The cameras are in steel boxes to protect them from elephants, the boxes are bolted to brackets 150 mm long and the brackets are bolted to steel poles at a height of either 500 or 700 mm above ground level.
The poles are 40 x 40 mm mild steel angle, either 2mm or 3mm thickness. The poles are driven deeply into the ground. The mechanical problem is that elephants push the cameras over; they bend the 2 mm thick angle through 90 degrees at ground level, or twist it through 180 degrees. They bend the 3 mm thickness through 45 degrees.
I have videos from the cameras as they are being wrenched around and most of the work is done by the elephants’ trunks, with some kicking and stamping once the pole is bent over. Elephants are alleged to be able to lift 350 kg with their trunks. How hard the they can kick is an open question. So my question is; what size and gauge angle iron or square tube would I need for a pole that could withstand twisting when 350 kg is applied sideways to a 150 mm lever bolted at right angles to the pole, without exceeding its elastic limit (camera aim is critical so the pole needs to recover after an elephant has tried to bend it) . And, similarly, what pole, standing 1 m out of the ground, could withstand being pushed at the top by an elephant – say 500 kg sustained force.
Thank you.
Specifications for elephant-resistant steel poles http://www.skepticforum.com/viewtopic.php?p=584279#p584279by Williamhdc » Tue Jun 20, 2017 5:17 am
This is probably simple for an engineer, but I’m a zoologist and analytical chemist and so I would rather ask those who know. I have camera traps out on the African bush, that are monitoring the responses of leopards to artificial scents. The cameras are in steel boxes to protect them from elephants, the boxes are bolted to brackets 150 mm long and the brackets are bolted to steel poles at a height of either 500 or 700 mm above ground level.
The poles are 40 x 40 mm mild steel angle, either 2mm or 3mm thickness. The poles are driven deeply into the ground. The mechanical problem is that elephants push the cameras over; they bend the 2 mm thick angle through 90 degrees at ground level, or twist it through 180 degrees. They bend the 3 mm thickness through 45 degrees.
I have videos from the cameras as they are being wrenched around and most of the work is done by the elephants’ trunks, with some kicking and stamping once the pole is bent over. Elephants are alleged to be able to lift 350 kg with their trunks. How hard the they can kick is an open question. So my question is; what size and gauge angle iron or square tube would I need for a pole that could withstand twisting when 350 kg is applied sideways to a 150 mm lever bolted at right angles to the pole, without exceeding its elastic limit (camera aim is critical so the pole needs to recover after an elephant has tried to bend it) . And, similarly, what pole, standing 1 m out of the ground, could withstand being pushed at the top by an elephant – say 500 kg sustained force.
Thank you.