Crush / Rollover safety impacted by glass roof or panoramic roof?

[calisnow]

One selling point for the Model S is the famous story of how it "broke" the testing machine which tried to crush it. I *assume* that test was conducted with a solid metal roof.

Any engineers here who can comment on how much, if any, crushing resistance is likely to be traded away for a clear view in the panoramic and/or new all-glass roof? I know Tesla strengthened the car in other ways per Elon's public comments after the all glass roof was implemented earlier this fall.

The all glass roof is sexy and I'd rather have it than pano on my next car for the clear view from the interior. But I always assumed the cross bar in the center of the pano roof provided additional structural support.

I have zero mechanical experience and only one year of undergrad physics so I am probably wrong on this. I do have some experience surviving horrific car crashes however so crash survivability is always on my mind.

 

[calisnow]

Nevermind. I give myself the dead horse meme because this was discussed in another thread.

 

[ecarfan]

I am not an automotive engineer or an engineer of any type. But my guess is that most of the strength of the roof comes from the B pillars and the cross piece connecting them. I believe those parts of the car's structure are essentially the same whether the car has an all metal roof, pano roof, or the new glass roof. If that is correct than I think the amount of force required to crush the roof will be the same for those three versions.

 

[Patrick W]

Could someone point to the other thread on this subject? I can't find it. Thanks!

 

[Zetopan]

Follow this link to read about the additional body strength added along with the all glass roof.
Tesla Model S gains optional all-glass roof with reinforced body structure

 

[Patrick W]

Follow this link to read about the additional body strength added along with the all glass roof.
Tesla Model S gains optional all-glass roof with reinforced body structure

Thanks. I just traded in my "old" S with sunroof (which I rarely used) for a new S with all glass roof (and v2 hardware). I trust Tesla to make it safe but am interested in the discussion referenced above by the original poster.

 

[CHG-ON]

@ecarfan is exactly right. The AL roof is simply there to block the sun . All the strength comes from the A, B (mostly) and the C pillars. The roof adds no strength at all. Maybe a little torsional rigidity, but I really doubt it. It's the boxed frame effect of the pillars all being joined together that does the work. However, the breaking glass could be an issue, as opposed to a crumpled, but intact AL roof because you'll need a dustpan to clean it all up.

 

[Patrick W]

Ok, I admit it. I'm not a car guy and I had no idea what a car pillar was. But thanks to Wikipedia and for others who may not know:

Pillar (car) - Wikipedia

A, B, and C Pillars. Meaning: The A pillars on your car hold
either side of the windshield in place. B pillars start where the
driver and passenger-side windows end as you look backward
along the length of the car. C pillars hold the sides of your
car's rear window in place.