acceptable angle of deflection for temporary support Answered
I am in no way an engineer. I'm trying to figure out what is an acceptable angle of deflection for a combination frame and hammock support. I'm thinking of using the the 80/20 t-slot beams. I want something that is portable, easily assembled/disassembled for moving, and lightweight. I'm go to make a box in our garden to protect our plants and when the corn is big enough, move the box around to make a hammock support(chicken wire around the bottom part to keep the critters out). It's basically a box 6 feet wide, 8 feet long and about 6 1/2 feet high. 4 beams to make a rectangle on the bottom, 4 uprights(1 in each corner), and another 4 beams on the top to make it more rigid. Chicken wire will keep the pests out but let me in to relax until the corn is too high and I move the frame. :) I'll put the hammock diagonally from pole to pole; total weight with me and the hammock is about 250 pounds. It will be anchored to the 2 uprights with 300lb chain at each end.
Using the angle of deflection calculator from 8020.net, I found some beams that had 5mm deflection with 150lbs of dead weight in the center of the 6 foot span. I thought that even if I anchored the hammock to the center of the 6 foot span, that would be 300 pounds, more than the 250 max the hammock and I will be. And anchored in the center of the beam is the worst case scenario since I'll be anchored to the corners.
But is that an acceptable amount of give in the beam? It's not meant to be permanent. I won't be in it more than 2 or 3 hours tops.