[T3] A new T-34 owner?

[Jim Adney]

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?

Otherwise, this is very interesting info to have. Thanks!

> Assuming that 7000lb load acts on a two inch square plate and the
> floorpan is 0.050 inches thick and mild steel with a Ultimate strength
> of 50 ksi and thus a shear strength of 38 ksi. 

> 7000lbs / (0.050" x 2" x 4) = 17.5ksi.  

> That is a factor of safety of just over  2 and assumes that the plate
> is pulled straight up through the floor.  The reality is that it will
> likely twist and only load one edge of the plate significantly. 
> Taking that into account, you probably only have a bit over 2" of the
> perimeter of the plate doing much for you rather than the full 8". 
> That means the local stress in the floorpan is something like
> 56ksi...so much for that factor of safety. 

> This is one of the reasons I went with the reinforcement and
> attachment method that I did. 


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Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
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