Bent Frame - Part Deux

[ShadowsPapa]

Maybe. As the frame is designed to bend up in the event of an impact it might actually be the rebound force that does the damage. This could be why the bend is up in the middle.

Actually it's designed so the rear of the frame goes down and the frame sort of surrounds the differential. The frame is not designed to bend up at the rear, it's made to bend down like an up-side-down V.
We need to look at it not as a bend up in the middle, but a bend down at the rear. There is no bend "up". The middle is where it belongs, the rear is down.

You think guys with that sort of truck don't go out and do worse than this?
The forces coming down on the structure of this car are in the tens of thousands of pounds!
Then take a truck with weight on it............

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[AmishMike]

@ShadowsPapa You look young in that video!!!

 

[ShadowsPapa]

@ShadowsPapa You look young in that video!!!

LOL - I'd sure not treat MY Eagle that way. As it is I cracked the joints at the roof/A-pillar one time.
I know that guy destroyed the suspension and undercarriage of that rare car. I bet the floor is cracked, shock mounts bent or broken, even worse.

If I had one of those I wanted to take out and beat, I have a pair of frame connectors I'd put in place first!

 

[bleda2002]

Actually it's designed so the rear of the frame goes down and the frame sort of surrounds the differential. The frame is not designed to bend up at the rear, it's made to bend down like an up-side-down V.
We need to look at it not as a bend up in the middle, but a bend down at the rear. There is no bend "up". The middle is where it belongs, the rear is down.

You think guys with that sort of truck don't go out and do worse than this?
The forces coming down on the structure of this car are in the tens of thousands of pounds!
Then take a truck with weight on it............

The frame is HSS so it has a tensile strength between ~36000 psi to possibly over ~75000psi. Its easy to get giant numbers from physics for force but the other thing to remember is potential energy is only so much. Now imagine how big the force needed to be on that truck to stop in 12 inches and then bend a box frame that has a tensile strength that high and it becomes a lot more unlikely that unless he jumped it a rediculous height, or had some kind of extreme weight on the hitch just desert running isnt going to do it.

 

[syreeves]

People are looking at that backwards - as cause and not effect. That's a RESULT, not a cause.
The scraping is the result of jumping or bouncing off hills and coming down hard. It's not what caused it.
IMO, the dealership was correct in looking at that receiver as a SIGN of what came before.
It's a clue, a RESULT, not a cause.

I think you and I are already saying the same thing. The scraping would not have caused the frame issue, but certainly it is evidence that this vehicle has been driven in a way that tests its limits. I think the problem I have overall is that a lot of us have probably scraped their trailer hitch AND in the absence of any other evidence to the contrary, a scraped trailer hitch should not be enough to void a warranty. Nor is admitting to overlanding with 700+Lbs in the bed.

At the end of the day I don't see how it is possible to bend the frame of ANY JT without abusing it irresponsibly.

 

[ShadowsPapa]

Tensile strength has little to do with bending -
tensile strength is the maximum load that a material can support without fracture when being stretched.
We aren't taking fracture as a result of stretching.

HSS can mean high speed steel or hollow structural steel.
Assuming HSS is the latter, it has nothing to do with whether or not it can bend.

It can bend and frames have areas in them that are DESIGNED to bend- they are bend or crumple points where the frame is weaker and it's designed to bend in a specific spot and in a specific way. Check the YT video that was posted a few pages back. It shows perfectly how these are actually designed to bend and at specific spots.

 

[AmishMike]

I jumped a '78 El Camino about 3' off the ground with a SBC and TH350 in the bed with no problems.
Used to bolt them together and set them into tires then strap them down for winter traction. I was 17 and kind of forgot about them when I followed my buddy over the hill at a high rate of speed. Got very lucky that day.

 

[ShadowsPapa]

I think you and I are already saying the same thing. The scraping would not have caused the frame issue, but certainly it is evidence that this vehicle has been driven in a way that tests its limits. I think the problem I have overall is that a lot of us have probably scraped their trailer hitch AND in the absence of any other evidence to the contrary, a scraped trailer hitch should not be enough to void a warranty. Nor is admitting to overlanding with 700+Lbs in the bed.

At the end of the day I don't see how it is possible to bend the frame of ANY JT without abusing it irresponsibly.

And that's what I'm thinking - there's more to this story, it wasn't driven in a manner that avoided any abuse. Parts of the story were left out. You can't bend a frame without some "abuse" or doing things while ignoring the laws of physics and machines/levers.
You don't bend frames without some abuse. If the frame cracked from normal driving, that's warranty, but to expect a bent frame to be covered under warranty - hmmmmmm....

As was posted well over a year ago when I had a receiver mount "Rack" or platform on the back of my truck with 6 concrete blocks each weighing about 60-70 pounds, because it was BEHIND the bumper the impact on the suspension was well beyond what, say, 300 pounds in the bed would have been due to the leverage. People forget physics - levers, the forms of energy and so on.
Having a spare tire carrier on the receiver meant that spare tire that weighed perhaps 90 pounds had a whole lot more impact than a spare in the bed due to the distance from any fulcrum.
That youtube video where the "engineers" talk of such things - there's info there that's good, and some that's just not so (like the bigger tires being an issue) - and the comment section has some great info as well.

I jumped a '78 El Camino about 3' off the ground with a SBC and TH350 in the bed with no problems.

SBC is only what, 400-450 pounds and it would have been centered over the axle?
I know the SBC engines don't weigh as much as an AMC engine which is about 500 pounds.
I can lift a THM350 so they aren't all that heavy (a hell of a lot less than the THM400!)
So you had only maybe 550-600 pounds of engine and transmission in the back, likely centered over the axle. What were the shock mounts like on those El Caminos? I can't recall, been years since I worked on one! That's where I'd expect trouble. I've seen guys ram shocks clean up through the "floor" on some cars - look back of the rear seat and there's the top of the shocks staring at you.

 

[bleda2002]

Tensile strength has little to do with bending -
tensile strength is the maximum load that a material can support without fracture when being stretched.
We aren't taking fracture as a result of stretching.

HSS can mean high speed steel or hollow structural steel.
Assuming HSS is the latter, it has nothing to do with whether or not it can bend.

It can bend and frames have areas in them that are DESIGNED to bend- they are bend or crumple points where the frame is weaker and it's designed to bend in a specific spot and in a specific way. Check the YT video that was posted a few pages back. It shows perfectly how these are actually designed to bend and at specific spots.

Jeep calls it high strength steel frame, so i'm going to take their word its HSS.

We are infact talking about stretching metal, thats exactly whats happening is that we are stretching the frame rails upwards. Bending is a precursor to breaking so tensile strength does matter. Higher tensile strength, higher force needed to bend first. This stuff is really strong, it does not bend easy as it has a very high tensile strength.

There are crumple zones, usually in the front and the rear to aid in slowing down a crash and lessen the force in the cabin, a weak zone in the middle of the truck though is highly unlikely and would be a poor design since its where the most stress will occur.

Edit: There are plenty of reports where for boxed shapes, the yield stress where permanent deformation of HSS occurs is between 42000psi and 65000psi.

 

[ShadowsPapa]

Jeep calls it high strength steel frame, so i'm going to take their word its HSS.

We are infact talking about stretching metal, thats exactly whats happening is that we are stretching the frame rails upwards. Bending is a precursor to breaking so tensile strength does matter. Higher tensile strength, higher force needed to bend first. This stuff is really strong, it does not bend easy as it has a very high tensile strength.

There are crumple zones, usually in the front and the rear to aid in slowing down a crash and lessen the force in the cabin, a weak zone in the middle of the truck though is highly unlikely and would be a poor design since its where the most stress will occur.

It's a high strength frame, not high speed steel.
HSS means high speed steel - search Google for "what is HSS" and you'll find "high speed steel" every time.
We are bending the frame downward, not stretching anything upward.
Tensile strength isn't in play here - that's do to with stretching before it breaks - how much pull can it handle. Bolts need tensile strength. Structural rods, cables, etc. need tensile strength, rope, etc. - tensile strength.

These are being compressed, bend DOWNWARD, not upward.
Not sure where everyone keeps saying the frame is being bent up, it's not, it's being bend down.
If it was being bent UP the box would be touching the cab at the top. Frames are designed to bend DOWN and that's what this one did. NOT UP.
Nothing moved UP. Roughly the areas of the shocks on back the frame is DOWN.

I've done machine work, auto repair and restoration (including collision damage, straightening, removing dents and more for decades) and this is clearly a case of the rear being down. It's not like it was pushed up in the middle, it was smacked down at the rear.

Why do you keep saying it's high tensile strength? It's a high strength frame, not HSS. You read that into it and it's just not so.
Nowhere does it say that, Jeep never says that.
It's a high strength frame, normal frame steel. It's a steel frame that is strong. You are reading into it. No one says it has high tensile strength. No one but you.

We are not stretching except at the peaks of the bends in the crumple area, we are compressing and bending.
It's as if I put a piece of square tube in my press and supported one end and the middle and pushed down on the other end. The top of the tube bends downward, the sides and bottom crumple in, there's some stretching on the extreme bend points (where HSS would CRACK)
The only parts with any stretch are the extreme bend areas, the outer parts where the steel is shoved outward and bent. The inside of the bend is compressed a bit, the outside of the bend is expanded or yes, stretched along a a line.
Did you not watch that full YT video that was posted earlier? There ARE crumple points that aren't at the very front or rear.

Trust me, these are not HSS - that's high speed steel - used for cutting tools like drill bits and so on.
Thought just hit me - how could they form these frame sections or halves in a press if they were HSS? (my father was a UAW member who worked in a factory among all of the presses - including making frames for things)

 

[MrZappo]

It's a high strength frame, not high speed steel. The steel is normal frame material, but the frame is high strength. Not HSS
We are bending the frame downward, not stretching anything upward.
Tensile strength isn't in play here - that's do to with stretching before it breaks - how much pull can it handle. Bolts need tensile strength. Structural rods, cables, etc. need tensile strength, rope, etc. - tensile strength.

These are being compressed, bend DOWNWARD, not upward.
Not sure where everyone keeps saying the frame is being bent up, it's not, it's being bend down.
If it was being bent UP the box would be touching the cab at the top. Frames are designed to bend DOWN and that's what this one did. NOT UP.
Nothing moved UP. Roughly the areas of the shocks on back the frame is DOWN.

I've done machine work, auto repair and restoration (including collision damage, straightening, removing dents and more for decades) and this is clearly a case of the rear being down. It's not like it was pushed up in the middle, it was smacked down at the rear.

Why do you keep saying it's high tensile strength? It's a high strength frame, not HSS. You read that into it and it's just not so.
Nowhere does it say that, Jeep never says that.
It's a high strength frame, normal frame steel. It's a steel frame that is strong. You are reading into it. No one says it has high tensile strength. No one but you.
High strength, steel frame - is how it should be punctuated.
We are not stretching except at the peaks of the bends in the crumple area, we are compressing and bending.
It's as if I put a piece of square tube in my press and supported one and and the middle and pushed down on the other end. The top of the tube bends downward, the sides and bottom crumple in, there's some stretching on the extreme bend points (where HSS would CRACK)
The only parts with any stretch are the extreme bend areas, the outer parts where the steel is shoved outward and bent. The inside of the bend is compressed a bit, the outside of the bend is expanded or yes, stretched along a a line.
Did you not watch that full YT video that was posted earlier? There ARE crumple points that aren't at the very front or rear.

Trust me, these are not HSS - that's high speed steel - used for cutting tools like drill bits and so on.
Thought just hit me - how could they form these frame sections or halves in a press if they were HSS? (my father was a UAW member who worked in a factory among all of the presses - including making frames for things)

With the current 3.6 Pentastar, nothing on this thing is high speed .. Plus aerodynamically its just not feasible anyways ...

Do I have to do all of the heavy lifting around here ?

 

[bleda2002]

It's a high strength frame, not high speed steel. The steel is normal frame material, but the frame is high strength. Not HSS
We are bending the frame downward, not stretching anything upward.
Tensile strength isn't in play here - that's do to with stretching before it breaks - how much pull can it handle. Bolts need tensile strength. Structural rods, cables, etc. need tensile strength, rope, etc. - tensile strength.

These are being compressed, bend DOWNWARD, not upward.
Not sure where everyone keeps saying the frame is being bent up, it's not, it's being bend down.
If it was being bent UP the box would be touching the cab at the top. Frames are designed to bend DOWN and that's what this one did. NOT UP.
Nothing moved UP. Roughly the areas of the shocks on back the frame is DOWN.

I've done machine work, auto repair and restoration (including collision damage, straightening, removing dents and more for decades) and this is clearly a case of the rear being down. It's not like it was pushed up in the middle, it was smacked down at the rear.

Why do you keep saying it's high tensile strength? It's a high strength frame, not HSS. You read that into it and it's just not so.
Nowhere does it say that, Jeep never says that.
It's a high strength frame, normal frame steel. It's a steel frame that is strong. You are reading into it. No one says it has high tensile strength. No one but you.
High strength, steel frame - is how it should be punctuated.
We are not stretching except at the peaks of the bends in the crumple area, we are compressing and bending.
It's as if I put a piece of square tube in my press and supported one and and the middle and pushed down on the other end. The top of the tube bends downward, the sides and bottom crumple in, there's some stretching on the extreme bend points (where HSS would CRACK)
The only parts with any stretch are the extreme bend areas, the outer parts where the steel is shoved outward and bent. The inside of the bend is compressed a bit, the outside of the bend is expanded or yes, stretched along a a line.
Did you not watch that full YT video that was posted earlier? There ARE crumple points that aren't at the very front or rear.

Trust me, these are not HSS - that's high speed steel - used for cutting tools like drill bits and so on.
Thought just hit me - how could they form these frame sections or halves in a press if they were HSS? (my father was a UAW member who worked in a factory among all of the presses - including making frames for things)

There is an article on this site linking to it. The frame is indeed mostly High Strength Steel or even stronger, AHSS.

https://www.jeepgladiatorforum.com/...ignificant-high-strength-steel-content.49478/

"..while the frame is nearly 80 percent high-strength or advanced-high-strength steels."

High speed steel is a different item all together. HSS is high strength steel, it is not brittle it just has a stronger tensile strength and yield stress than regular steel. It is used widely in modern cars especially in the frame, pillars, and structural areas so that it can achieve higher strength for less weight. I keep bringing up that the jeep frame is HSS because people act like a few hundred or even a few thousand pounds will permanently deform this stuff. It wont, it had to be a MASSIVE impact, one that you would have definitely felt and known occured and would show damage to other areas of the vehicle.

Also we all say up because the middle is bowed with the bow being up. The force that produced it is down in the rear or the front, or both, but the bow direction is up else the top of the bed would be driven in to the cab.

 

[ShadowsPapa]

There is an article on this site linking to it. The frame is indeed mostly High Strength Steel or even stronger, AHSS.

https://www.jeepgladiatorforum.com/...ignificant-high-strength-steel-content.49478/

"..while the frame is nearly 80 percent high-strength or advanced-high-strength steels."

Yes, I know - but that's not HSS and it's not high tensile strength.
Don't confuse Jeep's marketing with HSS - not the same stuff.
And they still have crumple zones that bend DOWNWARD. You don't want anything bending up.
I've seen that page - was reading up on it before I bought mine in 2019.

 

[bleda2002]

Yes, I know - but that's not HSS and it's not high tensile strength.
Don't confuse Jeep's marketing with HSS - not the same stuff.
And they still have crumple zones that bend DOWNWARD. You don't want anything bending up.
I've seen that page - was reading up on it before I bought mine in 2019.

Thats not marketing, HSS and AHSS are desginations of steel. These arent the same steels you got even 10 years ago, this stuff is significantly stronger pound for pound than the old school steels.

Yes i know this is for the wrangler, but I cant find the exact one for the gladiator, I cant imagine its any weaker.

 

[AmishMike]

I married my HSS - High School Sweetheart.

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