Sniv's Custom Long Travel Build

[snivilous]

Well good news and bad news.

The main good news I drove it, the bad news is not very far. In my race to get it running I made some short cuts which ultimately bit me in the ass. The main one being that I didn't reinforce the shock mounts and gusset them, figuring they could take the loadings of normal street driving. The drivers side shock mount broke, nothing severe got messed up and it was during hitting a decent dip into a parking lot at 5mph or so to see how it would hold up. The mount is still attached and was able to support the truck on the one block drive back, but it definitely taught a lesson. If I continued going hard I could have it fixed and properly reinforced like it originally should of been by Thursday for going to Salt Lake City, though I am now much more wary of what I am doing and want to have everything properly reinforced for offroading or street use--also I have two tests in the next two days that I need to start studying for.
[MENTION=94914]turbo8[/MENTION] I will get pictures tomorrow if I remember.
[MENTION=9631]twitchee2[/MENTION] I'm not worried about the UCA bolts, the UCA takes low loadings and the shear stresses the bolts will develop is way under their shear strength. With that said, I will gusset the bolt tube and it will be tied into the shock mount.

Here is a picture I snapped after it was moved into the driveway and I was adjusting the coilovers. [MENTION=55855]zopperman[/MENTION] I don't know if it's looked down upon, but could this be used as the T4ROTM photo? If not since the poll already started then no worries! Though this picture is more accurate representation of what I'm doing than the stock setup of the current photo.

 

[turbo8]

That is why I was asking for pics of the upper shock mount. Keep in mind Under braking ,the upper arm and mounts take a lot of load.

 

[twitchee2]

My thought was if you hit something to side, the bolts themselves are not the issue. The issue i see is the verticals the bolts are going through are going to want to bend outward with a side load. a through bolt does not allow independent movement of the mounts quite as easily.

If you boxed the sock spring columns where you cut it i think all would be good!

Just some constructive criticism. Overall, everything looks great. keep up the good work and get those shock mounts beefed up!

 

[MTD]

My thought was if you hit something to side, the bolts themselves are not the issue. The issue i see is the verticals the bolts are going through are going to want to bend outward with a side load. a through bolt does not allow independent movement of the mounts quite as easily.

Basically the idea of a double shear joint being stronger than single shear.

 

[MTD]

It's looking good sniv! it is unfortunate that you had to rush it with those gussets, but I am sure once you get it all gusseted and re-welded you should be fine. What steel are you using?

 

[Troymclure]

Definitely could use some gusseting on those upper arm mounts as everyone else said. They may not see much load, but it wont take much to bend one side of the mount as its essentially just a 1/8" thick piece of steel holding it up. Otherwise looks good!

 

[snivilous]

It's looking good sniv! it is unfortunate that you had to rush it with those gussets, but I am sure once you get it all gusseted and re-welded you should be fine. What steel are you using?

Just normal mild steel, I'm assuming it's A36 and its ultimate stress is 36ksi for all my calculations. I'll model the gussets in solidworks and do proper analysis on everything this time around.

 

[Brilliant]

Just normal mild steel, I'm assuming it's A36 and its ultimate stress is 36ksi for all my calculations. I'll model the gussets in solidworks and do proper analysis on everything this time around.

Out of curiosity, how did you derive your design to loads. Simple 4x static loads or something more interesting?

 

[snivilous]

Out of curiosity, how did you derive your design to loads. Simple 4x static loads or something more interesting?

I posted on dezert rangers asking about A-arm design and one guy commented saying on his team they used 10G frontal, 5G vertical, and 3G radial. He said they used G ratings so the actual force numbers were based on the trucks weight. I then assumed a 1250lb weight distribution to each tire and applied those figures and then added a 25% margin (1.25 FoS). I calculated all of this for the lower arm, figuring it took the majority of the loadings (and all the vertical loadings) and back calculated what the loadings at the tire/hub were and then figured out what the UCA loadings were based on the reaction about the hub.

I'm definitely no expert on how to go about the loadings, in the thread the guy even said that was a hard part of suspension design was figuring out what loads to design to. And then of course I'm just calculating everything statically, I figure I'm not gonna be pushing the truck anywhere near as hard as an actual race vehicle and compared to A arms you see from Total Chaos or Camburg mine appear to be built way stronger (debatably). So my figuring is it's okay to not get into more complex analysis involving dynamics (which I hate) since the arms appear to be built tougher, and are designed to specs for a desert car and then an additional factor of safety.

If you're interested, this is the thread: A-Arm Design Questions Tons of good information on it, specifically post 36 where the race guy explains where he got his numbers.

 

[MStudt]

I posted on dezert rangers asking about A-arm design and one guy commented saying on his team they used 10G frontal, 5G vertical, and 3G radial. He said they used G ratings so the actual force numbers were based on the trucks weight. I then assumed a 1250lb weight distribution to each tire and applied those figures and then added a 25% margin (1.25 FoS). I calculated all of this for the lower arm, figuring it took the majority of the loadings (and all the vertical loadings) and back calculated what the loadings at the tire/hub were and then figured out what the UCA loadings were based on the reaction about the hub.

Can you translate this to English?

It's looking good so far. Keep up the good work.

 

[shootmymime]

Can you translate this to English?

It's looking good so far. Keep up the good work.

i understood it. must be a mechanical engineer terminology.

ive given some thought about your upper arms and how one guy mentioned the forces on it when the vehicle is breaking.

yours is welded together in multiple pieces where as other companies are bent tube and only welded in around the joints and balls. With the moments placed on those arms id really like to see where and what one fails first, plus what forces it takes.

but im sure the tires will slip before the uca fails under load from slamming on the brakes.


Toby she looks good.

ps. will you 48" hi-ligt still jack it up enough?

 

[MTD]

ive given some thought about your upper arms and how one guy mentioned the forces on it when the vehicle is breaking.

yours is welded together in multiple pieces where as other companies are bent tube and only welded in around the joints and balls. With the moments placed on those arms id really like to see where and what one fails first, plus what forces it takes.

but im sure the tires will slip before the uca fails under load from slamming on the brakes.

His welds should be stronger than the material that the rest of the arm is made of if the welds are good quality. The compound angles his arms make will actually be stronger than tube as well. The reason you see larger companies use a single piece of bent material is because it is much cheaper to produce that way. With welding costing ~$100 an hour it doesn't make sense for them to do a complete welded unit.

My concern is that the mount for the A arm is not through bolted which means the only thing stoping those mounts from developing a moment and moving is the flimsy stock shock bucket. I would see if I coud find an nice long G8 bolt to run through the bucket and the two heims.

 

[MTD]

or you could sleeve those inner bolts somehow.... The upper A arms see most of their loading from the inboard of the vehicle to the outside so there is no need for any gusseting of their mounts.

 

[snivilous]

i understood it. must be a mechanical engineer terminology.

ive given some thought about your upper arms and how one guy mentioned the forces on it when the vehicle is breaking.

yours is welded together in multiple pieces where as other companies are bent tube and only welded in around the joints and balls. With the moments placed on those arms id really like to see where and what one fails first, plus what forces it takes.

but im sure the tires will slip before the uca fails under load from slamming on the brakes.


Toby she looks good.

ps. will you 48" hi-ligt still jack it up enough?

The 10G frontal load should account for braking. And the Hi-lift should be fine, though it'll be sketchy and I haven't tested it. My 18" jack barely pulls both tires off the ground from the differential cross member.

or you could sleeve those inner bolts somehow.... The upper A arms see most of their loading from the inboard of the vehicle to the outside so there is no need for any gusseting of their mounts.

I'm going to run a gusset from each shock mount tube down to the frame and have it integrate with that tube to help react the moment applied to those tubes, again with everything properly analyzed.

Here is a picture of the failure I experienced, not what I was anticipating would fail originally but it makes sense since all the stresses are concentrated on those vertical pieces.

 

[JBurt]

So how did you get to the airport?

 

[snivilous]

So how did you get to the airport?

Took a shuttle down, which I swear tracked worse than the 4Runner did when the alignment and suspension was screwed back in July. On the plane now so this marks a pause in the build until Monday!

Should have the shock mounts reinforced next week since we are moving to a new house in the next two weeks or so.

 

[Brilliant]

I posted on dezert rangers asking about A-arm design and one guy commented saying on his team they used 10G frontal, 5G vertical, and 3G radial.

I'm definitely no expert on how to go about the loadings, in the thread the guy even said that was a hard part of suspension design was figuring out what loads to design to.

If you're interested, this is the thread: A-Arm Design Questions Tons of good information on it, specifically post 36 where the race guy explains where he got his numbers.

I'll check out the thread, thanks.

Validate any assumption and keep track of them. Id also recommend walking a prof or more senior student through your results. Another set of eyes doesn't hurt. Interesting project that's for sure, best of luck.

i understood it. must be a mechanical engineer terminology.

Also made sense to me, but my studies were anisotropic structural mechanics. :tongue1:

 

[snivilous]

I'll check out the thread, thanks.

Validate any assumption and keep track of them. Id also recommend walking a prof or more senior student through your results. Another set of eyes doesn't hurt. Interesting project that's for sure, best of luck.

Yea, I reference my dad for almost everything who's a PE in Civil and does mostly structures for work, but certainly doesn't hurt! It'd be nice to get senior design project credit for it...

 

[Brilliant]

Yea, I reference my dad for almost everything who's a PE in Civil and does mostly structures for work, but certainly doesn't hurt! It'd be nice to get senior design project credit for it...

Thats good. I've watched this thread and thought... hmm if assumptions are wrong or an oversight is made, thus guy ends up in a bad spot. Good to hear you have another set of eyes checking your work.

I was thinking along the same lines for credit. Depending on your school's resources you could probably get into the lab and do some test as well. I had access to some composite manufacturing tooling, the machine shop, and the test labs. I manufactured parts and verified analysis by test, wrote a report, and got credit for it. Sounds like you could parlay this into credit as well.

 

[snivilous]

So I got back from CO last night, had an awesome weekend back home and with the girlfriend

Today I got hauling on the build again. To start things off, here is another more clear picture of how the original shitty rushed setup failed. The whole top section of the stock shock bucket that the tubes were welded too sheared off, though the rear of the plate was still on.

Here's a "final" picture before I started tearing it down.

In the process I found a very big problem, initially I was thinking I had a leak in the brake line somewhere but soon found the culprit:

That's right, after a single drive around the block my BRAND NEW shocks with their "fancy" high temperature more expensive seals is leaking. Lesson learned about going with the cheaper shocks... No one answered the phone for all my calls, I'll send them an email and I better get a new seal kit ASAP.

I then moved into removing more from the truck after pulling both shocks. I decided to cut out everything on the top and combine my UCA mounts and shock mount and run an engine cross brace. This will be much cleaner, stronger, and easier to modify/fix/tune. Additionally, I will grind down the UCAs welds and shorten them to fix my camber (mainly the drivers side is too negative), and I will move the UCA mounts 2" higher to compensate for the uniball spacers which is messing up my geometry causing the tires to go to negative camber at droop and I would rather they go positive.

This is as it was a little while ago, though I had opened it up more. I also cleaned up some areas of the wheel well that had now useless pieces.

The deadline is Friday, because we are moving on Friday. This SHOULD be a fairly quick process, cutting out the shock bucket was easier than I thought and the new mount geometry is fairly simple. It will essentially look like an A, with two vertical pieces going to the UCA mounts (which will now be in double shear as well) and will maintain the anti-brake dive angle thanks to the heims ability to still be functional despite both sides rotating on different axes vs bushings, and then a cross brace, then two angled pieces going up and meeting where the shock will mount. Another angled piece will then go up and be the start of the cross brace.

Originally I was going to have two cross braces, one near the UCA mounts and one the shock would mount on and then have the diagonals intersect further up but because of the brake booster this isn't possible. I am also debating how to go about the cross brace, it would be easiest to go right over the engine but the hood would have clearance issues. I am considering making a rectangle of tubing that goes around the engine... What I really want is a fiberglass hood setup to clear the brace going over the engine and then have it then tie into the firewall to increase Euler buckling... But we'll see, right now the job is to get each shock tower setup and then figure out the cross brace. Everything will be fully gusseted to the frame and the cross tubing in the tower, as well as probably a gusset on the outside of the frame to add some redundancy outside of just the engine brace, though that may be an issue clearing the coilover. Will work a bit more tonight and then almost all of tomorrow!