daily doubler build

[Bray D]

Alright, here's what I did. I took all of those stress values that are annotated on the pics I posted, put them into a spreadsheet, and found the average stress for all 4 slider geometries in those two locations (rock contact and the top of the slider above the rock).

Here's what I got:

Since these are stress values, obviously lower is better. The small grouping to the right compares the 4 geometries, their average stresses in each situation, as well as the maximum stress (at any location) that was specified by SolidWorks.

Looking at the numbers, the 2"x3" skinned with .125" strap has the lowest average at the contact of the rock, as well as the lowest max stress. All 4 variations are quite similar in the average stress on the top of the slider.

It is very evident that the thicker material on the bottom will resist denting much more than just the .125" wall. The 2"x4"x.125" sees the most stress in that area, as expected. The skinned .125" wall 2"x3" (resulting in a .250" wall thickness) has the least stress in that area - also as expected. This is enough for me to rule out the 2"x4".

The reduction in stress due to a thicker wall is enough for me to rule out the un-skinned 2"x3".

The differences in stress on the top of the slider between the skinned 2"x3"x.125"wt and the 2"x3"x.1875"wt isn't great enough for me to warrant the .1875" wall tube. It is heavier (44.45lbs) than the skinned 2"x3"x.125" (40.54lbs) and doesn't provide the same dent resistance.

I'll skin 2"x3"x.125" with .125" strap and be happy with my decision.

I did a little more work to see what the final strength improvement would be over my original sliders (skinned 2"x3" vs. 1" sch80).

Comparing the bending stresses based on geometry, the new design will be just over 10 times as strong as the old one.

In theory.

 

[RangerSVT]

With the design and research you have done, I'm thinking 2x4 .125 wall with a 4" .125 flat stock (strap) along the bottom of the slider....
SVT

 

[Bray D]

I don't think the added weight would outweight it's performance benefits. My old sliders got rocked, often, and they finally gave up the ghost.

The design I've landed on is (calculated) over 10 times stronger and weighs just over 40.5lbs.

I modeled it real quick, skinned 2x4 would weigh almost 47.75lbs. It's an added 15lbs total (whoo hoo right?). I see it as unnecessary weight. Before long I'll have an 8klb truck if I don't try to minimize weight every chance I get.

Like Kage mentioned earlier, you can have the strongest slider in the world, but if your supports bend it's no good. I'll be modeling and running simulations on the supports next.

I think the skinned 2x4 wouldn't be as dent resistant as the skinned 2x3 due to the larger surface area. It would be stronger in bending, but not much. The 2x4 in my spreadsheets should be very similar to how skinned 2x4 would act in bending.

After all of this work, I'm pretty well stuck on skinned 2x3.

 

[railman]

thanx for all the analysis

but, since I already have 2x4 .250 wall, I think that is what I will make my sliders out of.....



we both know I need to protect my rockers now


or I could just keep my hammer handy

l8r, John

 

[RangerSVT]

I agree with that, what about adding a brace underneath the brace coming off the frame (like in a "A" frame setup), with the bottom bar ending in the middle of the 2x3?? This should add considerably to the stress point. Im also thinking of taking the flat bar and pitting a slight bend in it the length if the slider, creating an angle iron effect, but without that much angle. Basically, it would underlap the 2x3 and the support bar. Since angle iron is stronger than flat bar, it would add to the strength without adding weight... Thoughts??
SVT

 

[97TrailRigDD]

Most of the hard hits are going to be to the outer piece of tubing in my experience. My sliders are 1.5" 0.120 wall round tubing and I have cut the outer pieces off once and replaced them but still have the original tubes under the pinch seam.

 

[Kage]

...blah blah blah.. In theory.

Fawking Engineers, allways throwing out pretty pictures with numbers that don't mean squat




(Thanks for throwing that up, I think that's the frist stress analysis I've ever seen done on sliders )

.. I see it as unnecessary weight. Before long I'll have an 8klb truck if I don't try to minimize weight every chance I get.
.....

You make it sound like a bad thing to have a heavy truck

Most of the hard hits are going to be to the outer piece of tubing in my experience.....

That's actually a pretty valid point. While I'd bet it'll still be strong enough, I wouldn't mind seeing those pretty pictures of that too if you're bored. There's been a time or two where I've come down in a notch (or ledge) and caught one or both slides hard on the outter portions of them. Not that it was a big deal as the frame attachment pooints defelected enough for it not to matter

 

[86 slo-vo]

The outside edge will take some hard hits, but with 2x3 I don't think he will have too much problems.

I had 2x3 3/16 with no tube kickers or plating and I smashed on them pretty hard. I can think of several times I dropped the entire weight of the truck on them repeatedly.

 

[Kyle M.]

My sliders are 2x6, .1875 wall and hold up great to my abuse. I think .125 plated with .125 will be great.

 

[Bray D]

Thanks for all of the input guys. I'm not saying that my analysis is 100% correct either, but I like playing around with this stuff and it usually sparks some good discussion.

One error I already know of is the averaging of the stresses. They're just random points that I chose and averaged them. I think I'll go in and create a split surface that's at the same location on all of the models and have SolidWorks average it for me. We'll see what those number look like too.

but, since I already have 2x4 .250 wall, I think that is what I will make my sliders out of.....

We both know I need to protect my rockers now

Yes, sliders are a necessity. haha

I agree with that, what about adding a brace underneath the brace coming off the frame (like in a "A" frame setup), with the bottom bar ending in the middle of the 2x3...

That's how my old setup was with the sch80 pipe. I'll model that as well as what I'm thinking for the new design - rectangle cut so it tapers down to where it meets the slider. That way I'll keep the most height possible in the support maximizing the resistance to bending.

... Since angle iron is stronger than flat bar, it would add to the strength without adding weight... Thoughts??

Angle is strong due to its geometry. You are thinking correctly, though I'm not sure it would be worth the effort. Welding it with a gap between the "angle" and the slider's base would make it so the .125" thick angle would take all of the load initially = denting of the 'angle'. A flat strap won't add as much strength to the bending of the entire member, but since there's contact, it transfers the load directly to the base member - essentially acting like a .250" thick plate rather than 2 individual .125" plates.

Even though it's minimal, you would also lose clearance by putting the angle on the bottom.

It's up to you, but if it were me (I guess it is kinda me since I'm building sliders as well) I would leave the plate flat.

Most of the hard hits are going to be to the outer piece of tubing in my experience.

Absolutely. I thought about this as well. I'm limited with the material can use though, since I can only bend 1.75" OD tube. I can vary the length that they stick out, but that's driven by the protection required by the sliders. I'll just have to build them to what they need to be and see what happes.

I figured if I bend the wing, I can easily cut it off and build a new one. If I bend the base member, I'm kinda fawked.

Fawking Engineers, allways throwing out pretty pictures with numbers that don't mean squat

It's all in good fun.

(Thanks for throwing that up, I think that's the first stress analysis I've ever seen done on sliders )

Talking about the slider wing........I wouldn't mind seeing those pretty pictures of that too if you're bored.

I would like to as well. I'm struggling to place the load under a round member. It creates a line load and SolidWorks won't solve it.

I could put a split surface on it and apply load to that, but then it's not as "real life". With the rock, I put a "no penetration" constraint between the rock and the slider (so the slider would deform around the rock) and I made the initial contact surface area a 1" diameter circle so I avoided the point/line loading.

I'll play around with it and see if I could come up with something worthwhile.

 

[Bray D]

Another thought is 2x2" square. More weight reduction, smaller surface area so less chance of denting, cheaper. It's approaching just using 1.75" tube, but a quick hand calc shows that 2"x2" is still 2.5 times stronger in bending than 1.75" round, and 6 times stronger than my original 1" sch80. 2"x3" (no strap) is 3.8 times stronger than 1.75" and 9 times stronger than the 1" sch80.

2.5 and 6 vs 3.8 and 9. Hmm....

I'll have to run the simulation to see what it looks like under load.

Any qualms with running 2"x2" vs 2"x3"? Less sliding surface area, but the same area to mount the supports to.

 

[Bray D]

I did some analysis with 2x2 material, and created cut surfaces on the other models and re-ran the simulations. Then I had SolidWorks calculate the max, min, and average stress on those cut surfaces and output all the data into a spreadsheet. I've gotta organize all the info, then I'll update with my findings.

On to real world stuff, my old traction bar was a joke (I still can't believe I half assed it like I did) so I built a new one this weekend. I took a risk ordering a joint from Ballsac Fabrication, but they shipped it and it made it to me in decent time so I can't complain.

I started by gusseting the frame side joint. I just welded the bushing housing to the crossmember initially :shakinghead:

Then I built the top bar.

The redish brown specs isn't rust - it was my attempt to apply primer. Spray paint didn't work today so I didn't get anything painted.

Anyways, here it is all trussed and welded.

I ran the lower bar parallel to my driveshaft. It sits about 1.5" lower than my d-shaft, so it should provide some decent protection.

The joint and shackle setup. Only one side of the shackle for mock up.

So that's done, now I've just got to get it painted. It's supposed to be in the 50's for the next couple days, hopefully I can get it painted and installed.

 

[Bennybooster]

is that the ruff stuff traction bar bracket kit?

 

[Bray D]

Yep, ruffstuff axle bracket and shackle. Used their poly bushings too.

 

[Bennybooster]

nice, I will need one eventually