Tesla Upper Control Arm CRACKED

[Frank88]

Do you have a credible source stating they are extruded? Their shape does not look like something which would be created by an extrusion process, which is basically stretching and forming.

Yes
2012 Tesla Model S Signature Performance Suspension Walkaround
This closer look shows a couple things. First, the toe link (red) and the upper link (yellow) are the only two links visible topside, which means the lone upper link is strictly a camber link. Second, both are made from aluminum extrusions that have been sliced to the desired thickness like so much Play-Doh or deli meat.

Also if you look carefully you can see the marks of the extrusion die.

 

[Frank88]

If you look at some of the secondhand links for sale on Ebay you will see that many of them are about ready to snap.
The circular holes are being stretched which means they have gone beyond the elastic limit and are in the plastic limit stage.
This means that fracture is the next thing.

Not only are these parts weak initially but repeated tension and compression will lead to metal fatigue.
I am not trying to be funny.
This is a lethal defect caused by a bad choice of material for the suspension components.

 

[mongo]

If you look at some of the secondhand links for sale on Ebay you will see that many of them are about ready to snap

Parts on E-bay come from salvage/ totaled cars, not a good sampling of part quality/ longevity. I don't see any examples of stretched links currently.

I wonder if much of the damage seen in wrecked cars is due to being extracted from their resting spot by a winch attached to the wheel. Not a lot of places to tie off on...

 

[Lloyd]

I have a pair I will sell you if you want to replace the fractured ones. Pm me!

 

[jaguar36]

Casting, extrusion, aluminum or steel, none of it matters for making a safe part if it is properly sized. Sure it might not be the lightest part possible, but if it is sized properly for the loading the part sees you can make it using whatever you want. Aluminum can be very ductile or very brittle depending on the alloy, heat treat and manufacturing process. A brittle failure does not necessarily imply a defective design. Most modern aircraft structural components are made of very brittle aluminum alloys.

Your part was clearly poorly made, and has no bearing on the design of the part.

 

[McRat]

Yes.

This closer look shows a couple things. First, the toe link (red) and the upper link (yellow) are the only two links visible topside, which means the lone upper link is strictly a camber link. Second, both are made from aluminum extrusions that have been sliced to the desired thickness like so much Play-Doh or deli meat.

Also if you look carefully you can see the marks of the extrusion die.

Yup. Aluminum normally cracks with the 'grain'. This is why on all critical components, grain direction is specified and verified.

The grain runs the wrong way to resist forming cracks. Just an unburred edge, a rock chip, a tool mark, could start a crack forming and the grain direction force the ding to act as a stress riser.

This was a really bad way to make something. It might work, but so might a piece of oak.

This should have been an I-beam forging. Sort of like a connecting rod in an engine.

That being said, those pictures of massive porosity in an an extrusion is fishy. That looks more like a tragically poor job of welding.

 

[Frank88]

Yup. Aluminum normally cracks with the 'grain'. This is why on all critical components, grain direction is specified and verified.

The grain runs the wrong way to resist forming cracks. Just an unburred edge, a rock chip, a tool mark, could start a crack forming and the grain direction force the ding to act as a stress riser.

This was a really bad way to make something. It might work, but so might a piece of oak.

This should have been an I-beam forging. Sort of like a connecting rod in an engine.

That being said, those pictures of massive porosity in an an extrusion is fishy. That looks more like a tragically poor job of welding.

 

[Frank88]

Plenty of opportunity for things to go wrong.
https://www.researchgate.net/public...xtrusion_and_their_impact_on_operational_cost

 

[mongo]

Any reason to think this link was not designed to deform/break under impact as part of the crumple zone in a side or offset impact?

 

[JRP3]

I doubt it. Suspension parts would seem to be outside of the crumple zone of the passenger compartment in a side impact. Plus I don't think those voids were part of the design

 

[mongo]

I doubt it. Suspension parts would seem to be outside of the crumple zone of the passenger compartment in a side impact. Plus I don't think those voids were part of the design

Ha.
My comment was directed toward the forged I-beam level of strength reference.

 

[McRat]

Any reason to think this link was not designed to deform/break under impact as part of the crumple zone in a side or offset impact?

Because extrusions tend to snap cross grain. To make something absorb energy, you want it to deform. Like run the I-beam center vertical from impact vector, but still run grain lengthwise on part.

 

[Frank88]

Indeed, like linking to troll sites which use unrelated photographs of collision damage to promote a false narrative. It hurts your credibility. Clearly your control arm had a flawed casting, the pictures prove it. It doesn't prove that this is a fleet wide issue. You could have saved a lot of time and aggravation by posting them from the start.

Is it safe to assume that it is NOT a fleet wide issue?

 

[JRP3]

I believe failure rates would be much higher if it were.

 

[Frank88]

Perhaps not all the owners have reported each failure.

 

[McRat]

Perhaps not all the owners have reported each failure.

Only a small fraction of car owners visit enthusiast sites.

Most are on Facebook texting pics of what they had for lunch on their cellphone while driving 75 mph and staring down at their crotch.

 

[JRP3]

Even with that nut job Keef reporting almost every single accident to NHTSA they haven't felt there are enough to issue a safety bulletin or recall.

 

[Frank88]

Take a closer look to this failed arm. It look to me extremely porous, the center material is like sand, I can scratch it with my finger. It looks that the only structure that counts in that part is the thin metal shell, however porous, full of gas bubbles from casting.
I will order a third party inspection of that part from an independent structures testing laboratory, then I will post the report here and fill in reports to safety authorities.

Hi George
Did you file an NHTSA report yet?
That Tesla which suddenly veered off the road into a pond had the back wheel missing.View attachment 303296

The wheel and tire are undamaged. Even if the wheel received a heavy impact in the crash why did the suspension snap off so easily?
I've damaged a tire. even bent a rim. I've NEVER had the entire suspension snap off.

 

[FlatSix911]

Looks like Porsche is using the same supplier ... Porsche 918 Spyder Hit With Another Recall

Parts of the rear suspension could crack, and Porsche intends to replace the parts with stronger pieces.
Sorry, Porsche 918 Spyder owners because you’ll need to take your supercar to the dealer for a recall. Porsche will repair 305 examples of the 2015 model year 918 in the United States because the connecting shafts for the suspension control arms could crack. Porsche’s analysis found that the “connecting shafts of the longitudinal and transverse control arms might be vulnerable to cathodic stress corrosion cracking.” The company believes that the problem affects the components’ long-term reliability, and they require replacement.

Porsche will replace these parts with more stronger versions, and the work will require seven to eight hours to complete. The automaker reports that it has no reports of actual incidents related to this problem. The 918 Spyder has been subject to multiple recalls. The first was all the way back in 2014 when five of them required replacement of the rear axle control arms. Unspecified chassis components also needed fixed later. In 2015, yet another campaign addressed possible damage to the wiring harness, and the firm had to inspect the entire production run for a potential problem with the seatbelts in 2016. Porsche also previously repaired the front lower control arms for possible cracking at the ball joints.

While the 918 Spyder appears recall prone, it’s Porsche’s only dedicated supercar for the foreseeable future. The company intends to wait for a breakthrough in battery technology until creating a successor. The firm’s current plan is for the new model to be fully electric and with better performance than the 918 in terms of acceleration and track times. The good news is that Porsche already has models on sale that are significantly quicker than the 918 Spyder. For example, the latest 911 GT2 RS can lap the Nürburgring about 10 seconds quicker than the 918.

 

[Frank88]

Good to hear that Porsche is doing the right thing.
Now, how about Tesla?