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Optimized Geometry

GEspo

Member
Interested in having your current or future susp geometry optimized using 3D math and engineering software? IFS IRS 2 or 4wd..
 

51rcr

Well-Known Member
Curious what some of the going rates are to scan, copy existing parts for those that have pre cad or hand made parts? Lowers, uppers, knuckles, lower links?
 

michael.gonzalez

Well-Known Member
You looking for a quote? I don’t have a 3d scanner but I do have experience designing sheet metal assemblies for lowers, uppers, spindles, links and the fixturing needed for manufacturing.
 

51rcr

Well-Known Member
You looking for a quote? I don’t have a 3d scanner but I do have experience designing sheet metal assemblies for lowers, uppers, spindles, links and the fixturing needed for manufacturing.
No. but all my stuff is hand built and since this was put up i wanted to see what the cost ranges were just for duplication. And also curious about improved design cost have run people. I dont figure anyone will say prices except those that have had work done. Wonder what the cost differences between a scanner and and pin point arm cost. Since it really is about the time to copy the part.
 

GEspo

Member
My background is math and computer programming, worked on building AI algorithms for a genetic co for a bit.. Applying that knowledge which is complicated mathematical optimization, to the many equations known as the DW. I happened to find a great suite of 3D simulation software which will perform the optimizations: imagine the near infinite possible points for the DW.. for example for my personal project I was able to shrink the camber curve: ride height -2.4, at 9" bump -5.4, -9" droop -1, so net change is probably around 4.5deg. Also designed for roll camber which was minimized at the same time, so 5 deg body roll I get about +1.5 deg camber. This is for a 4x4 so I located the exact points that will give me 6mm of axle plunge.. means I can run non plunging inner and outer CV's.... I'm offering to help with your geometry.. since this is new to me there is no charge, or you can donate to this potential new business venture if you like what you see.
 
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partybarge_pilot

Well-Known Member
Wonder what the cost differences between a scanner and and pin point arm cost.
It all depends on the guy picking points out of the scan. If it's anything like the tards we have in our CAD dept, your better off using calipers and punching the numbers in. A-arms are just as fast to draw up as to try and convert from a scan. Whole chassis? Might be worth a scan, maybe........ Still going to require a lot of clean up and making everything match side to side.
 

MTPyle

Well-Known Member
Hasn't the tech been available for awhile to optimize geometry? My truck is super old and was built in 2012. It was designed fully in 3D CAD with "optimized" geometry. What tech is there now that would help? maybe CFD for air flow or better stress test to make things lighter and stonger? but I don't see how you can improve the geometry of something that was already designed in 3D.

Not trying to be negative, just dont see where the advancements are to make improvements in geometry.

Mike
 

michael.gonzalez

Well-Known Member
I think he is referring to custom suspension. Not OE trucks.

Some geometry is built into the truck. (Lower Control Arm Mounts, Upper Control Arm Mounts, Rack and Pinion Width and location, etc)

Some geometry can be built into the arms, upright, and other components. (Modifying an OE truck)

Or if building a custom chassis, You can control a lot more.
 

GEspo

Member
This is a new field for me, so any comments are totally welcome. Yes you are correct that mathematical optimization has been around for decades, however processing power has recently reached a place that any home computer can accomplish most tasks. If you’d like you can send me a few dimensions and we’ll see if I can come up with any improvements. The result would be for example.. if you raise a mount 1.5” or shorten/lengthen an a arm etc.. that of course assumes existing design. From what I can tell, and I’m just entering the field, not much of this is happening, referring to 4x4 IFS.. Also what are you referring to as “optimized”? What program did the optimization? From what I gathered the large usu CAD suites didn’t have that capability(could be wrong and I’d like to know that)..
 
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partybarge_pilot

Well-Known Member
What program are you using? I have used a couple different geometry calculators over the years. Those were all 2D though and didn't give the whole picture when you add in things like castor gain.
 

43mod

Well-Known Member
Too many variables to count when choosing your optimum set up. Pick your goals and see how close you can get. CAD means nothing if it GIGO. Chalk , some flat bar , tape measure , degree wheel , skill , knowledge , experience and lots of time can do it better than bad CAD.
 

michael.gonzalez

Well-Known Member
GEspo. Are you able to solve dynamics simulations of any simplicity? Say a simplified 2-d vehicle(with m, mass, and a moment of inertia) with front and rear suspension(with k, spring rate and c, damping) traversing over a line-plot representing terrain at a given speed (v)?

Outputs being the angular and vertical position of the car at any point on the line-plot.
 

isdtbower

Well-Known Member
Michael G.: Well that might be his next step but I don't think he is there yet. I think I did notice that he took into account body roll. What body roll does to the wheel angle to the ground. That would be a good 2D step right there, if he could "optimize" and print out the "caster" change tro the bodya and the ground with body roll. The next step gets to your point on suspension and how much body roll you would get while braking AND turning. I found that I could see fairly consistent body roll numbers from video. You can also see the wheel angle to the ground AND the tire deflection. Body roll for a TT seems to be 5* or less. A Ultra4 can be 10* body roll easily.. For TT steering, maybe a good number to optimize to would be 15* steering with 5* body roll. A Ultra4, maybe 22* steering and 10* of body roll. This is when caster gain starts kicking in and 3D would be better than 2D.

Then you would have to see how that effects straight line performance whee there is little body roll but lots of suspension activity. From what I have seen there are some huge caster gain numbers to the frame, toward bump that don't seem to bother the drivers. 5-9* on some. I believe trying to get good camber to the ground in turns or upsets..

When you get to this point, it seems very few arm mounts are parallel anymore. A few have benefited by this "optimization." It makes a difference.........

With 4x4 IFS. Any Axle plunge is a bad thing and has to be kept into the "optimization" process.

Hopefully GSepo is on the right track, and some numbers are better than none. I think some of the college suspension classes get into this but by the time the students start to grasp the good ideas they graduate and move on. Few, then have the resources t crunch the numbers.
 

michael.gonzalez

Well-Known Member
I think some of the college suspension classes get into this but by the time the students start to grasp the good ideas they graduate and move on. Few, then have the resources t crunch the numbers.
You are 100% right. That is me right now. I suppose I can dedicate more personal time to this endeavor although now I'll have to pay out of pocket for the simulation program.
 

GEspo

Member
I’m using a suite that is purely math based and much like matlab.. Yes all basic physics scenarios can be accounted for. There will definitely be constraints, a few being setup of non suspension related components and screen to shop fabrication variance, hoping to keep that to a min. I’m in the process of building out a full vehicle dynamics program w/ 3D simulation since the software has a tire package that I added. At this point just modeling in 3D with no rolling, just flexing and looking at the numbers.
 
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GEspo

Member
Curious what some of the going rates are to scan, copy existing parts for those that have pre cad or hand made parts? Lowers, uppers, knuckles, lower links?
I use a machine shop here in Tucson that seems to be very reasonable $$ wise and has 3D printing and possibly 3D scanning capabilities. PM me and I’ll send u their details.
 

MTPyle

Well-Known Member
I sent you a PM, look at your inbox
 

isdtbower

Well-Known Member
I am a big fan of the 3D printing. Some years ago ('15) "we" were designing "our" first aluminum 4x4 upright. Dallas had a scale model printed in France as printing was relatively new then. It was a lot easier to get my head around how to hold the alum block as I went about machining it. From the printed part, I made a full scale part from presswood. I could tell real quick where the weak spots were and we added or changed the thinking around those areas. I was also fortunate enough to be on Jason Sherer's garage team to see what survived Ultra4 in CroMo and the community upgrades early on in IFS.

I always wanted to print out the arms also so I could physically see the frame mounting geometry in play. Once you get to this level it is amazing how geometry just a couple years ago is "obsolete" to the way of thinking.

Sorry pics so big. The geometry didn't change in the process, but the parts sure did. All this was hand cranked so some profiles were changed and some Bigg A radius tools purchased thanks to ebay. The fun is in the chase sometimes. (7075 t6, Wide 5, series 30 CV, Wildwest Innovations IFS, Spidertrax Hub Unit )

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51rcr

Well-Known Member
if you guys are into 3D printers check this company out. They helped us out racing. I know they are always moving forward and working with new materials for special applications
 

GEspo

Member
"This is for a 4x4 so I located the exact points that will give me 6mm of axle plunge.. means I can run non plunging inner and outer CV's...."

Finally getting back to modeling geometry after a month designing the triple bypass in the systems modeling software. I should say axle plunge is .5mm not 6mm. Hoping to have a solid vehicle dynamics program by the end of summer for multi purpose use, any type of 4 wheel vehicle. By then should have a site launched for the new racing company with videos and specs on what is offered. I'll update here once ready. Thanks.
 
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isdtbower

Well-Known Member
Great that you are boiling down to those dimensions. You may want to still recommend a plunging CV on the half shaft inner. It probably doesn't articulate more than an easy 20-25*. That number is not ultimately what the CV is capable of but one where frictional heat overcomes reliability. Also when you are adjusting the upper heims in the final alignment, you don't want to have to worry about the location of the inner CV. (Nothing is that perfect or will stay that way) The priority should be tire and wheel alignment and not CV location. Especially when it can be easily-ish avoided. Cheers.
 
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