[T3] A new T-34 owner?
Jim Adney
jadney at vwtype3.org
Sun Jul 3 10:09:10 PDT 2011
On 3 Jul 2011 at 13:55, jaransont3 at comcast.net wrote:
> From: "Jim Adney" <jadney at vwtype3.org>
> On 1 Jul 2011 at 15:19, jaransont3 at comcast.net wrote:
>
> > A 35mph front crash into a fixed object generates approximately a 25g
> > decceleration! The number can be much higher at higher speeds,
> > depemnding on what you hit. Federal Motor Vehicle Safety Standards
> > (FMVSS) require testing at 25g front impact, 20g rear impact and seat
> > belt pull testing at 16Kn (3500lbs) on both the lap and shoulder belts
> > simultaneously. This means the outer fixed end of the belt sees about
> > 7000lbs of load in this quasi-static test.
>
> Don't you mean the INNER end here?
>
> ***************************
> Actually, both the inner and outer lower anchors see the same load
> (assuming the retractor and fixed end share a common anchor point)
> since both the shoulder and lap belts each act on those anchors.
I guess I wasn't thinking about 3-points with a retractor.
If you assume a retractor, and assume the "quasi-static" situation
where the shoulder belt tension is everywhere equal, then you would
certainly get 3500# from each one, both applied to that lower outer
anchor point. BUT do the vector addition, and the sum would come to
something slightly less than 7000. ;-)
Once I start to think about vectors, however, I have to admit that
the same thing would apply to the inner anchor point.
Still, I'll agree that considering the angle between the vectors,
7000 is probably a pretty good number for each point, even the outer
upper!
This all gives me one more reason to like the '70-1 belts best. ;-)
--
*******************************
Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
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