Quote:
Originally Posted by Quacker
In figure 21 and 22 you can plainly see the energy absorbing crush-boxes in front of the original beam, between it and the car body attachment pads. Also note the design of the beam behind and to the side of the crush box where it is meant to yield and bend if the outer wings are hit hard. The tow hitch is totally unyielding in every respect and only the body's safety cage and towbar strength is left as protection. The rear energy absorbing engineering is very much compromised. To what exact extent it is compromised, only the design and testing engineers at Volvo are likely to know. Regardless, they would not wish to highlight this point or put a precise measure on it, I'm sure.
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The section of the original beam makes it extremely stiff and rigid, hence the crush boxes (if that is what they are).
I believe that the different section of the towbar may make it somewhat more "elastic", avoiding the
need of some other device to absorb energy, although there is another item mounted in figure 36.
The question remains why Volvo opted for a different section and didn't simply weld the tow bar
to the same structure as in the original beam. The more "elastic" property of the round section may
explain that. It is reasonable to assume that Volvo isn't throwing overboard the safety of their cars
when a towbar is fitted, but perhaps this can't be judged from seeing a drawing or a picture.
But not being an engineer, I can't speak with the same confidence as you do.