I don't know what you mean by introducing a stress raiser but attaching a web below the bottom effectively deepens the existing bar which improves it ability to withstand bending in the vertical plane.
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I don't know what you mean by introducing a stress raiser but attaching a web below the bottom effectively deepens the existing bar which improves it ability to withstand bending in the vertical plane.
You can attach a web below the box section of the A frame, but you need to weld it onto the sides of the A frame box section, not the bottom of the A frame box section, otherwise you will make the entire assembly weaker.
A stress raiser is an imperfection (weld, cut, etc) in a piece of steel which gives a fracture (crack) a place to start.
If you look at a trailer A frame from side on and imagine the stresses going through it you will notice that the sides are in a bending moment (trying to curve up at each end to make a smiley face) while the top section is in compression (trying to be shorter to match the curve of the sides) while the underneath section is in tension (trying to be longer to match the curve of the sides).
While you might not actually see any curve, trust me, that is what is happening. The higher the ball weight the higher the stresses. If you induce a stress raiser in the section under tension (ie weld to the bottom of the box section) you are introducing a site for crack propogation. Hence my comment to weld to the sides of the box (which are not under tension, but are in a bending moment).
it depends on how you attach what where....
a single point bracing 2 bars together is a stress riser and can if not applied correctly cause the upper bar to bend over the lower bar or vice versa.
a web is a series of joins that are quite long, relatively speaking and are not as prone to failing.
My strengthening rail spans the whole length of the drawbar with multiple stand-offs. The tension is now in the lower rail rather than the base of the original drawbar. The drawbar was strengthend over 30 years ago and has not shown any problems in that time.
I reckon the shocks mounted at that angle are about as useful as tits on a bull, too cheap and nasty to buy the correct length shock, regards Frank.
It's the civilian version of the military trailer. I wonder how much it will go for?Quote:
Originally Posted by mowog
Ok the answer to material costs.
Between $1000-2000 depending on the mix of used/off cuts or new steel.
I have been looking for one of the ADF Track Trailers on line... They are very had to find for sale.
If I could find a used ADF Track Trailer then that would be the way to go...
Tank,
At 45 degrees inclination, those dampers are 50% effective - not too bad.
Least of my worries when it comes to "a frame" independent trailer suspensions.
Who in their right mind decided that seperating DS from PS loading on a trailer would be a good idea? Solid axles share load and forces left to right. Independent suspension on a tripod is irrelevant, loads are only DS to PS wheel and the hitch.
A solid axle with four link / aframe / cross links will do all that an independent setup will do and it will NOT have toe or camber issues with overloading.
rant over,
Steve
I've seen a few drawbars done like this and it seems to work with the stands coming off the bottom plate of the RHS. I suspect a you say that the stress is now taken by the new bottom plate and the load where the A-frames bottom plate is moves to somewhere closer to the centre of the new section where no or minimal stresses occur...... except when the ball weight is lift and the additional bottom plate deflects under compression, but I doubt those forces are too significant in relative terms.Quote:
Originally Posted by Graeme
But, if you weld across the top plate of the draw bar, especially where it comes out from under the trailer box, and even along its length it will crack eventually - especially with non load sharing tandem axle trailers.
I fitted full-length support because less than full-length would have caused both the weakening of the existing draw-bar at the end weld point and the end weld point would have been where there was a change in rigidity of the drawbar, which would have added to the possibility of failure at that point. With full-length, the drawbar operates as a single ladder span.