Yield strength test for the ME's (and good info for the rest of us).

[Weasel]

Please explain this. If bending is the failure mode expected, why on earth would it not be the important factor.

Crash, you mentioned placing an airbag at some location on top of the arm. This is going to change the load conditions...

Yeah I don't get that either, bending is pretty important. if I get a chance I'll draw something in SolidWorks that i think would work well as long as your willing to spend the time to make it.

 

[CRASH]

Please explain this. If bending is the failure mode expected, why on earth would it not be the important factor.

Crash, you mentioned placing an airbag at some location on top of the arm. This is going to change the load conditions...

Not an airbag, he bag is going on the axle tube. Maybe a sway bar mount and MAYBE a bump stop. I can see how that would change the load, but if I have it measured right, it will go very near the axle end of the wish bone.

Spent some time measuring under the rig last night, and I can't see using an arched member. It's either going to have to be straight links, or a kink about 2/3 of the way back from the member.

This thread has already made me re-think some assumptions, and I've learned something. Now we just need a final calculated answer!

Guessing sucks.

 

[XJ_ranger]

Not an airbag, he bag is going on the axle tube. Maybe a sway bar mount and MAYBE a bump stop. I can see how that would change the load, but if I have it measured right, it will go very near the axle end of the wish bone.

Spent some time measuring under the rig last night, and I can't see using an arched member. It's either going to have to be straight links, or a kink about 2/3 of the way back from the member.

This thread has already made me re-think some assumptions, and I've learned something. Now we just need a final calculated answer!

Guessing sucks.

do you know how to use solid works?

see PM

 

[Zebaru]

Please explain this. If bending is the failure mode expected, why on earth would it not be the important factor.

I said bending isn't all that is important...

There are a bunch of things involved here, and it seems possible that one could build a section that handled bending really well, but wouldn't really work for a link.

It isn't sexy, but square or rectuangluar would probalby be the easiest, cheapest solution...

Travis

 

[Dirk Pitt]

do you know how to use solid works?

see PM

Solidworks will be great for modelling it, but it's not going to tell you what material to put where...

 

[XJ_ranger]

Solidworks will be great for modelling it, but it's not going to tell you what material to put where...

well - i thought we had agreed on using mild low carbon steel

and with the COSMOS FEA that we did for the Baja, we could choose a material, and look at the diflection based on our loading....

 

[David Taylor]

Not an airbag, he bag is going on the axle tube. Maybe a sway bar mount and MAYBE a bump stop.

The end of that axle tube is starting to look a little crowded. It's not sexy but how can you beat leafs if your keeping the body ? Are you willing to go through the floor with links ?

 

[CRASH]

The end of that axle tube is starting to look a little crowded. It's not sexy but how can you beat leafs if your keeping the body ? Are you willing to go through the floor with links ?

Yes, upper wisbone only. And I'm all about sexing it up.

 

[Weasel]

Cosmos is sort of mickey mouse, Abaqus is much better, and no Solidworks won't tell you where to put the material but it is good to figure out what shape you want. What kind of mounting end are you thinking? Dimensions? Now 2-3 bent members are out but maybe one bend is possible?

 

[CRASH]

Cosmos is sort of mickey mouse, Abaqus is much better, and no Solidworks won't tell you where to put the material but it is good to figure out what shape you want. What kind of mounting end are you thinking? Dimensions? Now 2-3 bent members are out but maybe one bend is possible?

I'm going to sketch this out and send it to Opie for input into SolidWorks. Basically, picture a very large V, the point of the V is mounted on a crossmember that is 38 inches forward of the centerline of the axle tube. The ends of the "V" are approximately where the spring perches are for the OEM leafs. So about 36 inches, IIRC.

The single bend would have to be 24 inches back from the crossmember in order to clear the floor.

 

[goodburbon]

pre bending square tubing would be silly since the deformations would serve to weaken the stronger structure, which is why you would choose it over round tube in the first place. Just make mitered cuts, and fab your desired shape with gutssets for excessive accidental lateral loading.

 

[goodburbon]

I just dreamt up a really wild idea.......what if you made your lower bracket just as planned, and for an upper bracket, a mirror image of the lower, only with the 2 outboard mounting points on the crossmember, and the inboard right over the chunk.......shouldn't even need a panhard rod ......

 

[CRASH]

Remember people, I have the ability to fabricate the structure completely, there is no need for cutting an mitering. I will simply cut the correct shapes out of pate and TIG them all together.

Just like the big boys do!

http://www.desertrides.com/features/vehicles/gordonTT/imagepages/DSC01987.php

 

[CRASH]

I just dreamt up a really wild idea.......what if you made your lower bracket just as planned, and for an upper bracket, a mirror image of the lower, only with the 2 outboard mounting points on the crossmember, and the inboard right over the chunk.......shouldn't even need a panhard rod ......

OMG, you're catching on!

You spent too much time debating Jesus, that's the plan.

 

[goodburbon]

I like that idea, and completely fabbed structure would kick serious ass



oh, and If I have saved one soul from being saved it was worth it.

 

[CRASH]

I like that idea, and completely fabbed structure would kick serious ass



oh, and If I have saved one soul from being saved it was worth it.

I'm trying to move beyond my angle grinder roots.

A fabbed structure, in my mind, opens up a whole world of possibilities, as it gets you a great combination of strength and weight savings with the proper thickness of metal at every point.

If I could find a competent heat-treat shop, I'd even consider 4130 sheet, as I can get it. The post weld treatment seems like it could get real pricey, real, quick, though. Maybe not, never priced it.

 

[BrettM]

CRASH, do you know what joint you plan on using for the single end of the wishbones? what about the double end?

 

[BrettM]

I'm trying to move beyond my angle grinder roots.

A fabbed structure, in my mind, opens up a whole world of possibilities, as it gets you a great combination of strength and weight savings with the proper thickness of metal at every point.

If I could find a competent heat-treat shop, I'd even consider 4130 sheet, as I can get it. The post weld treatment seems like it could get real pricey, real, quick, though. Maybe not, never priced it.

Have you contacted 66CJdean on Pirate? I know he does cryo, I think heat-treat also.

 

[CRASH]

CRASH, do you know what joint you plan on using for the single end of the wishbones? what about the double end?

1" Uni-ball at the point (106,000lb radial load rated).

Delrin or Poly at the points.

 

[BrettM]

1" Uni-ball at the point (106,000lb radial load rated).

Delrin or Poly at the points.

hmm, i don't really know jack about Uni-balls, but if it's good enough for trophy trucks, then cool. My friend built a 2.5ton YJ with the 1.25 Evo rebuildable heims, I like that they're easily rebuildable, and definitely plenty of beef. Of course with a wishbone, all of your articulation must be misaligned at the single joint... looks like the Evo goes 28* and a UniBall goes 32* (http://www.pirate4x4.com/tech/billavista/PR-Joints/index.html)

I used delrin on my wishbone, primarily because I had no triangulation in the lowers, and only around 24" seperation on the wishbone, so I needed something very stiff. I kinda like the idea of having a little bit of poly in a link suspension to reduce shock loads.