strut tower rip?

[Bernie Benz]

A good analysis of the tower loading Eric.  And there is the isolator issue
that the tower brace does not address, which further reduces negative
camber, my original design objective.

Thanks,  Bernie

> From: Eric_R_Kissell at whirlpool.com
> Date: Sun, 30 Jan 2005 09:19:46 -0500
> To: CL Wong <montesawong at yahoo.com>, 200q20v at audifans.com
> Subject: Re: strut tower rip?
> 
> 
> I have been reading this thread and one thing occurs to me:
> 
> The Bernie Brace is very easy to build - why don't more people have one?
> 
> The strut tower cracking is a fatigue failure, which results from two
> things - cycles and strain.
> 
> The Bernie Brace will reduce strain by spreading the stress between the two
> sides. Less stress means less strain.
> 
> When Audi reinforced the V8 they changed the distribution of the stress as
> well, which would reduce strain in the area that seems to crack. This does
> not mean that the movement of the top of the strut was necessarily reduced
> a significant amount, though it may have been. I have not looked at a V8,
> so I cannot speculate. It may be that Audi was tired of the occasional
> crack through the hole so they redistributed the loading to reduce some of
> the strain at the area prone to cracking. Total movement of the top of the
> strut may or may not have changed much.
> 
> The Bernie Brace makes a straight shot from the top of one strut to the
> other, so it is loaded as a column and thus very stiff. Note that the
> loading from side to side is always in compression, so column loading is
> appropriate. Any brace that does not go straight across will be loaded in
> bending and not as a column and thus need a lot more material arranged as a
> proper "truss" to be as stiff as the Bernie Brace. Furthermore, just
> stiffening the front of the strut tower will not provide that same
> stiffness to the rear of the strut tower and vice versa because of the
> "bending" or "rotation" of the strut tower front to rear. The Bernie Brace
> puts the extra stiffness right in the middle where it is most effective.
> 
> Again, the Bernie Brace is a very easy part to make, so why not just add
> one and see what you think?
> 
> Just wondering,
> Eric
> 
> 
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