Designing a Trailer: Determining Steel Square Tube Size

[sgmech1]

I am working on designing a trailer that will hold a load of 350lbs on 2 centered posts. It needs to have a safety factor of 3, so 1050lbs plus trailer weight. I am trying to determine the size of Steel square tube I must use. Any advice on formulas or methods of determining this? I would greatly appreciate it.

Thanks

 

[sgmech1]

How would I determine the shear stress on sqaure tubing if I am using ASTM A500 Grade B steel

 

[Mech_Engineer]

Without some better specifics for your geometry (like a picture) it's hard to give you any useful feedback. Remember: a picture is worth 1000 words.

 

[sgmech1]

What formulas are there for shear if I have a yield point of the material?

appreciate the help

 

[Mech_Engineer]

Why is load of the trailer supported by just those two points, instead of distributed across the trailer's frame?

 

[Travis_King]

I'd imagine that it's for something like a jet ski. Most of the weight will be directed on the two keel supports. There will be side supports to keep it straight probably, but they won't bear much load.

Is this for a personal or academic project? If it's personal, then just over design it. If it's for school or something, well, just look up "bending and shear in beams", "shear at welded connections"

 

[nvn]

sgmech1: (1) What is the distance between the centerlines of the tires? (2) What is the distance from the back tube centerline to the trailer hitch ball? (3) What is the distance from the back tube centerline to the front load point shown on your diagram? (4) What is the distance from the back tube centerline forward to the apex of the diagonal tubes?