Designing arms against buckling

[Paul Copioli]

Rick,

I knew it started with a T, but I always screw the name up (the video will NEVER leave my memory).

Every part of my message dealt with buckling, except the last sentence which mentioned dynamic conditions. I should have elaborated on what I meant by dynamic conditions, but I wanted to keep my message short. The point I was trying to make was that when dealing with buckling, mass is not a contributor to the critical load. However, when dealing with dynamic conditions (aka natural frequency, resonant frequency, etc.), mass is a big player. After re-reading the message, I can see how someone would make the buckling connection to the last sent ace. I apologize for the confusion.

-Paul

[Gdeaver]

Don't forget torsional stress. Allot of load analysis formulas ignore torsional stress because they are analyzing a load bearing beam in 1 or 2 dimensions. The arm will be subjected to torsional stress. We're using a 2" square tube with a 1" tube foamed and epoxied inside to account for these stresses. (fiberglass). Tube in tube can help also butted tubing can help.