Fractured Aluminum Skin

[Colorado Fun]

This happened on a long drive through I-70 the past couple of days on a trip to JC. We can’t figure out how it happened. No impact point marks, but there was a load noise. Two breaks also on the aluminum trim on the rock guard.
Has anyone seen anything like this?
Probable root cause?
Manufacturing defects?
Any help would be appreciated.

[PaulBristol]

I am not a fully trained failure analyst. I do have limited experience with fracture failure.

The rock shield is clearly stronger than the AS body skin. The skin gave way and the shield held. My guess is something fairly big hit the rock shield. Since you can't find marks or dents, the object was probably soft. It might have been a glancing blow from a deer or large bird. It might have been junk kicked up from the road, possibly a cushion or bag of something soft. Lots of possibilities.

I would advise my companies design department to improve the mounting bracket to spread the load where it attaches to the skin or to put reinforcement structure under the skin to support the bracket. I see the rock shield mounting surface has already been reinforced. There are probably other mods that would be better and cost less to build.

Submit an insurance claim. Some insurance adjusters are experts. Some are just administrators. Some will lie to protect companies assets.

Contracting with a failure expert to get a definitive analysis would probably cost more than the cost to repair the damage.

[Aerowood]

The skin cracked due to work hardening of the skin from vibration of the rock guard. Airstream does not reinforce the skin where the bracket rivets on as they should. This is a common problem which Airstream has known about for a long, long, long, time.

There are a couple of repairs, one is to replace the skin and do nothing to fix the initial problem which will most likely reoccur. The second is to install a reinforcement doubler either internally if the skin is replaced or externally if the skin is repaired

[SunchaserV]

CO Fun
I am a metallurgical engineer and agree that a top notch forensic look see is costly. That said, AS should look at this as they surely have some in house experts that will fairly consider this as a build or design issue rather than run and hide.

Aerowood raises some potential points regarding AS's well known failures. More importantly the long standing inferior design of the frame and skin at the front end may well raise it's head as a subset to FES failures.

But, the oft mentioned tongue weight % measurement, tow vehicle and hitch setup bears some thought too. Describe these areas for additional clarification.

Then comes I-70 whether due to speed, poor roads, winds or a passing semi. Regarding a bird strike - where is the blood, feathers and dent. Lastly, there could have well been a shift change during your trailer build period and things got screwed up. Thus, life with an Airstream goes on.

[CBWELL]

As Aerowood explained, this has been a problem for years. Not all trailers have this happen, but a combination of vibration, poor alignment at installation of the mounts which put extra stress on the skin, and extra pounding because of too high a tire pressure on either TV or trailer combined with incorrect hitch setup or weight bars all contribute to this happening. On my 1994 unit I had one of the mounts start to cause a crack in the outer skin, so I cut pieces from thicker aluminum that I purchased, and made oversize patches and used Bostik ISR 70-03 sealant/adhesive and rivets to attach the patch to the skin. I made the patch with nice rounded corners and after installation there was no more creacking.

[ROBERT CROSS]

It appears from your pic's that there is no backup for the mounting bracket to hold on to...only the skin.

Ours is mounted along a rivet line, which is likely giving a lot more support. Appears also that the mount design has changed

Bob
🇺🇸

[sfranklin]

My thoughts are that trailer could be over hitched. What I mean by this is that too much WD can put stresses onto the frame and front shell. This was also known to exacerbate the FES issue and my feeling is even with the added supports, could still lead to FES, but that's for another discussion. I have seen these kinds of tears a few times, this one being the worst I have seen to date. No strike happened that did this as has been pointed out. Something stressed this, but I cannot say for certain that the mount you show in your pic is in the area of the supplemental supports shown in my two pics.

One thing I'd like to share are these photos of the inside shell of an Airstream under construction- this was back in the day when you could actually walk into trailers in production. What you will note at some of the rock guard mounting points are reinforcements behind some of the mounting points. Understand these photos were taken nearly 20 years ago when I was visiting the factory. If those are still present in current designs, I can't say for sure as the tours today don't allow a lot of sticking your head in units being built, but I would think those bracket would still have to be there as mounting directly to the skin exclusively, clearly would not have any of the needed structural support and tears like this would be done in a matter of days not months, weeks or years as the skin alone is nowhere near robust enough to hold these in place. Not saying the brackets are a huge improvement, but they were there and did/do provide a bit more rigidity.

[Rolind]

I agree with vibration of the segment protectors as the culprit. We had a shocking amount of harmonic vibration and deformation in the segment protectors of our Basecamp at highway speeds.