TresCrows
Elite Member
Well, I am not retired anything and proud to be a wild and wooly civy and could care less anyway. That aside, I have some training and knowledge of metals and matierial strength and I am a bit confused as to why this is an issue? Most of these trailers you see are built from mild steel, probably a 1000 series alloy. I doubt it should be a concern if the trailer is sufficiently over built, fatigue life should be in excess of the remainder of your life. When the elastic limit is exceeded the metal takes a new shape--it bends, depending on the type of metal, working below the elastic limit to calculate fatigue cycle life--depends to what percent of fatigue strength the metal is worked repeatedly. If the metal is so oversized that it simply does not give then it is not "cycling" and limit life would be infinite excluding corrosion effects etc. If you want an expensive last forever trailer build it from heavy wall, 4130, chro-mo steel, seal the tubes and inject tube seal or linseed oil in the tubes and zinc chromate the exterior surfaces and then paint the hades out of it with polyurethane paint--something like Dupont Imron. That would be way overkill but the stuff has about 3 times the strength of mild steel, 30,000-50,000 psi vs 90,000-120,000 or better for high strength steel--4130 and similar high strength alloy steels. This is without reference to text, off the top of my head numbers and a vastly over simplified attemted explanation for a very involved and complicated subject I am not involved in on a daily basis. I doubt people calculate fatigue life of trailers, they just grab some chunks of steel, weld it up and say that looks about right. J
