Effect of manufacturer supplied sunroff on crashworthiness? 1

[austim]

As a retired structural engineer (bridges and other fun stuff ) I have been asked to comment on the likely effect of a sunroof on the crash worthiness of a 4WD (Toyota RAV4, if that matters).

Likewise, what about the resistance to falling objects? (eg tree branches falling after bushfire etc - my daughter is a volunteer firefighter, and lives in an area where such things happen).

I would like to think that Toyota (or any other reputable manufacturer) would have ensured that the strength of the structure around the sunroof would be roughly equivalent to the strength of the standard roof without any opening, but....


Please can any knowledgeable member shed any light on these questions?

TIA

 

[GregLocock]

I don't know, but "can of worms" is the phrase that springs to mind.

Most times that I have been involved certification/homologation is done on a model that approximates to either the most popular, or the one that is thought to be most likely to fail. This is done by negotiation with the certifying authority. I do not know how it is done with crash or roof crush.


Cheers

Greg Locock

SIGlease see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[BrianPetersen]

Normally, the sunroof takes the place of a section of plain ordinary sheet metal, without affecting the stiffeners that run the length of the roof along the sides or across the roof. The roof is not part of a crumple zone in normal front, side, or rear collisions, and unless the roof actually deformed in some way, it wouldn't have had an effect one way or the other.

As for resistance to falling objects, obviously glass can break. Glass in the side windows can break, too. It's no different, it's just another piece.

 

[austim]

HI, Greg and Brian.

Thankyou both for responding.

I much prefer Brian's response, since it gives me some reasonable moral support for my uninformed beliefs :-D , but I fully sympathise with that "can of worms" reference.

As it happens, my daughter has now decided to buy a vehicle with no sunroof, but we will be storing your valued advice away for possible future use.

Cheers,
Aus Tim