Story behind F450 pickup frame failure? (photo)

FishOnOne wrote:

ib516 wrote:

FishOnOne wrote:

Cummins12V98 wrote:
1999 VS 2013 technology!

Looks like Ford's technology beats RAM's technology when it comes to safety.

Link

You do realize that article is from 2012 and the Ram has a new 50k psi frame now right? LINK to current results

I'm fully aware of that... The post is still legit for cummin12V98 comment for '13 technology. The link I posted was for 3/4 ton trucks and in '13 RAM 3/4 ton trucks still had the same frame as the '12 models so the link is still legitimate.

Just trying to provide facts on such a subjective topic.

The video was of a Ford and RAM "DUALLY". I was referring to the trucks in the video. I am willing to bet my 11.5 Dually would not twist on the ramp either.

Add weight to the RAM I am sure it will twist some.

All things *WILL* fatigue over time being flexed/bent/etc

All things *WILL* fatigue FASTER at the stress raiser point(s)

Designers were taught that in engineering classes from high school on up

It is 'when' it will fatigue...starts out with micro stress cracks...both
surface and internal

Propagation to become ever larger cracks...till it cracks clean through

Alloy, hardness (whether alloy, working, temp, etc), cross section,
design attributes (designed stress raiser that are then mitigated by
design) factored by the type of force, frequency, amplitude...etc

ALL truck frames and even unibody/Monocoque flex under *ANY* kind of loading
No matter static or dynamic or both

The higher the natural frequency (harmonic) of any given structural
member, the longer it will take to fatigue....factored by amplitude,
which will shorten that time to failure

For a pickup, I'd spec it to have a minimum of TENS OF MILLIONS of
cycles, at max design spec loading for MTBF...during the warranty
period...plus a few for good measure (margin)

Pickups with this kind of load has very low frequency at any load

Increasing the box section and thickness will increase the harmonic
(frequency) vs this very low frequency load

BUT...if the load is over the spec MAXIMUM load...that will toss the
designed MTBF out the window.

Reason is that during the upper end of each load cycle (up and then down)
the material (metal in this case) will go beyond elasticity and into
plasticity

Once will leave it bent and not spring back

Too many times will start to introduce micro stress fractures that
will propagate into ever larger cracks till it cracks clean through

From the image...that trucks 'top' flange of the frame rail was fatigued
more than the bottom. So the bottom was still connected

If both cracked and the web cracked, then separation would occur

It's not anyone OEM is better than the other. Most engineers go through
the same basic courses in college

The main differentiator is the design philosophy of the OEM, eng
department and the biggie here...their bean counter management's
allowance of per-centage design margin or lack of any...

Bedlam wrote:
I would argue that crash test results involve the cab design and occupant restraint systems as much as the frame, so they are not a direct reference exclusively of frame strength.

Agreed. Frame strength may not play that much into crash safety. Modern cars crumple like pop cans in crashes today but occupants often walk away with minor or no injuries. 25 years ago when many cars still had heavy steel frames it was common for a car to be driveable but the occupants were severely injured. Of course trucks still have heavy steel frames but cab construction and restraint systems are what protects occupants, not so much the frame.

ib516 wrote:

FishOnOne wrote:

Cummins12V98 wrote:
1999 VS 2013 technology!

Looks like Ford's technology beats RAM's technology when it comes to safety.

Link

You do realize that article is from 2012 and the Ram has a new 50k psi frame now right? LINK to current results

I'm fully aware of that... The post is still legit for cummin12V98 comment for '13 technology. The link I posted was for 3/4 ton trucks and in '13 RAM 3/4 ton trucks still had the same frame as the '12 models so the link is still legitimate.

Just trying to provide facts on such a subjective topic.

I would argue that crash test results involve the cab design and occupant restraint systems as much as the frame, so they are not a direct reference exclusively of frame strength.

Hannibal wrote:
A chassis that flexes or bends under excess load rather than breaks in two from stress cracks? Are you suggesting you can't break or bend a Ram's chassis? I tip my hat to the Hemi and Cummins engines but, I'll take a Ford Superduty pickup over the Ram any day. The "moron challenge" in the video is totally irrelevant for everyday use of HD pickup trucks. Even real trucks flex.

Yet when I make this argument as to why the Tundra frame isn't under-engineered, I get called an idiot that doesn't understand metallurgy. Granted, I don't understand metallurgy, but I understand that ALL frames flex some to prevent breaking...

FishOnOne wrote:

Cummins12V98 wrote:
1999 VS 2013 technology!

Looks like Ford's technology beats RAM's technology when it comes to safety.

Link

You do realize that article is from 2012 and the Ram has a new 50k psi frame now right? LINK to current results

How does one control a truck when it can't keep it's wheels on the ground?

Hannibal wrote:
How dare you inject a voice of logic in an otherwise juvenile thread!:B

He did go kind of overboard there. :B

LOL!

Best I remember from previous post on this. The car trailer he is towing has a race car and a huge tool box mounted in the front.