Alls I know is it's nice to see rocket surgeons involved in the ol' Jeep TJ community in some form or fashion. Can never go wrong with that.
Corrosion resistant, light weight TJ frame
- Thread starter rowen01960
- Start date
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TJ Enthusiast
i didnt read all the discussion just the first page. this sounds like an amazing concept and it could be bery beneficial to may individuals. how would it do off roading in a situation where lets say the frame comes in contact with a rock or tree stump etc, how well would it hold compared to steel or possibly aluminum?
Ok ... I have started the TJ Frame ASSY, I am dismayed at the level of quality of the -582/-583 Frame Drawings/Specifications ... I was taught (1996) to always use the Buttline/CL as the XZ Plane, the FWD Axle Longitudinal location as the YZ Plane, and the FWD Axle Vertical Location as the XY Plane ... seems only the JK/JL Frames and later adhere to this concept.
Oh well another legacy drawing in need of renewal .... I should have a 3VU OEM ready to share on Thurs/Friday of this week. I need to run a simulation on that model in steel to correlate to the real OEM frame ...
I would like to have interested forum members review and comment on the deformation response of the OEM frame at 1/2/3G at GVWR ... there will also be an Eix (Long Bend deformation at GVWR) and a GJ (Torsional/Twist deformation at GVWR) ... support 3 corners of the frame load to GVRW and measure the droop of the one corner at the frame height ... this test would not be advisable if you have rust concerns in your current frame ...
Your responses will establish a lower, a mean, and an upper limit for 1G stiffness, repairs and/or mods to the frames should be noted as well ... this data will either show my model as utter BS ... or that it has some legs/validity ...hoping for the later ....
What kind of feedback, exactly, are you expecting? Most of the guys who frequent this website won't have any idea what they are looking at, let alone what it means. Not trying to slight anyone...just that you're speaking about pretty specialized engineering simulations...and if you don't do it for a living, interpreting them is next to impossible. Then, trying to co-relate the results of the simulation to real-world situations takes another leap of understanding.
I went to school for mechanical engineering, got my degree, and have spent the last 15 years working in the injection molding and assembly world...and I know I would not be any help trying to complement or criticize any of your results...at least without a TON of research and hand holding.
If you do post results, please be sure to post comparative data to the steel frame, and explain what it all means...down to 1/2/3G (factors of gravity).
OP
Not quite rocket science (although a very expensive CMC “cousin” is often used) ... but thanks for the pat on the back ... from a self proclaimed “red-neck rocket scientist”
You'll be selling it out of your shop. No one will touch it for 10%. Think 40% margin if you want to develop a distribution network. You obviously have the tech skills but it's a no go with marketing margins so thin.
Flex is a good thing in a Jeep. The reason frame body mounts are so thick is to allow flex. If yer composite does not allow flex, in the Jeep Trail Rated world it'll break.
OP
Good Question! The on-design point equivalency for impact damage is usually with 6061T6 guaged for required stiffness. HUMs will confirm if the allowable has been exceeded ... DAMTOL is an endless path and so reason needs to dictate the limit for a “get home” scenario ... a 3G decel will pretty much be the structural limit without signifcant wall thickness increase
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TJ Enthusiast
not trying to be rude but common english please. I kinda see where your going but my simple texas raised brain is lost lol
Be glad to, but to surmise in a nutshell with very few exceptions, they are cheap! No big surprise.
OP
I will have “hands on product” during Design, Static/Dynamic Testing, Durability/Field Testing and the Selection/Training/Auditing of JV manufacturing bond shops ... if there is no JV interest in evaluating a complete Technical Data Package for Limited Rate Licensed Manufacturing ... then it gets locked away.
If resellers are not interested in providing Customer Support for 750-1000$/Frame, I guess they wont be selling this product ... as they can add no real monetary value to the product... I would rather the End-User pocket the money.
... for direct to End-User/Consumer Sales ... think Ikea, Tesla or Apple, for upfitters that want quantity rates ... their yearly numbers will not be high enough to support a mfg process change which will require increased minimum yearly quantities of 1k-5k/y/5y (robots and automation)
Group buy quantity may get there but likely not sustainable for the required 5y amortization term....
Been in this “Rodeo” before ... too many times ...:-(
OP
Hey no fair ganging up!
Damage Tolerance or DAMTOL (Abuse) is unfortunately a marketing thing ... I design to the required Standards of Safety ... Marketing wants it to withstand an undefined level of user abuse ... I become frustrated ... Marketing gets angry with me because they do not want to be pinned to an allowable level of abuse ... resulting in additional material weight, cost of material, cost of labour to locate material.
Bad news for me ... so I will say the DAMTOL limit is defined by max 30% Bending Stiffness loss when dropped from 20m at GVW... you can get home in this frame ... but not much farther ... if all else survives ...
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TJ Enthusiast
Hey no fair ganging up!
Damage Tolerance or DAMTOL (Abuse) is unfortunately a marketing thing ... I design to the required Standards of Safety ... Marketing wants it to withstand an undefined level of user abuse ... I become frustrated ... Marketing gets angry with me because they do not want to be pinned to an allowable level of abuse ... resulting in additional material weight, cost of material, cost of labour to locate material.
Bad news for me ... so I will say the DAMTOL limit is defined by max 30% Bending Stiffness loss when dropped from 20m at GVW... you can get home in this frame ... but not much farther ... if all else survives ...
i see said the blind man to the deaf dog. just out of curosity are you gonna be needing tester vehicles. id be down for a free one to test of course
If thats 10%.... you are marketing a TJ frame for $9500.00 ??
I'm pretty sure you need to quit the development thing and do the market research thing cuz I don't think you'll find anyone willing to spend $10K on a frame for a $10K TJ.
OP
The Big Plan includes a 50kmile Field/Durability Test on 10 individually configured Frames ... these can only be provided once Static/Dynamic Tests (crush tubes) have been completed and the Load Spectra defined.. At that point (12-18months after kick-off) and, with approvals of the Beta Testors‘s Drive Plans the frames in their various configurations should be shippable. A build time of up to 12 months should be workable ... however the 50kmiles need to be completed within 12 months of vehicle completion ... Frame Ownership will transfer after test completion and data submission ... a black box will be provided ... this is not a Quick project ... but it will be done correctly ... with no surprises for anyone ...
OP
As I stated earlier, the ROM (not including a resellers 10%) MRSP would likely be between 7.5 and 10k for an OE spec to full mod spec (OTBD Dampers, raised Perches, Lowered Rod Mounts, etc etc) I cannot see it being higher as it would not correlate with a $/kg factor I established/demonstrated for FCA in 2014 on a RAM 3500 TXMBR (55%mass reduction, NVH equivalency, Durability and Abuse Test passes)
This Frame was/is not designed to compete with used metal frames, it is designed as an improvement to the OE steel metal frames in a short supply Global Market.
I hope this brings some clarity to what I am trying to do and the help I need to realize this product ....
OP
So to keep my “Red-Neck Rocket Science” FEA simulations real and of use in predicting things ... I need to correlate to some relatively simple Bending Tests in the real world ... Longitudinal Bending (4 corner) and Torsional/Twist (3 corner).
The Long Bend Test inolves measuring the Empty Weight of the Vehicle, then supporting the Vehicle Level on 4 Stands as close to the Wheels as possible ... measure the 4 Heights from ground to the contact surfaces ... then measure LH/RH Rail bottoms mid distance between the axles. Add sufficient centralizedweight to vehicle to achieve GVWR. Remeasure LH/RH Rail bottoms mid distance between the axles.
Torsion requires a similar setup/procedure but with 1 of the stands being lower than the other 3 ... FEA will determine safe test heights ...
The Steel OE deformation cases will be first out of the “gate” in order to correlate to your steel deformation test meaxurements. After I adjust the model to your nominal deformation results I can sub the composite material deck and provide first order deformation results ... these results guide the geometry and laminate scheme design process towards equivalent deformation ...
Worse or improved explanation?
OP
So a specialized “quick-change” Frame System that requires 2 “Highly” skilled personnel to re/re a 7500$ frame in <4 at “special” shop hour rates? ...
How about 2 FWD Crush Tubes from a 40% offset impact at velocity limit (45mph) in 2 mh? The 25% offset need to be simulated but I may be able to contain the energy wihin the allocated crush tube length ... ie no Frame Damage ...
I think insurance attractive numbers can be achieved ... however the traditional estimators guide book will need amendment ...
Body Mount/Isolator impact damage experience would be of interest to me ...
OP
“Skin-the-Game” ... current CAD WIP status ... TJ OE Specification Composite Frame with errors and ommisions ... to be remedied for official Forum comment release on Monday of next week ... note that this model has minor (hopefully) deviations from the actual steel frame ... a steel version will be available within a couple of weeks ...
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