[200q20v] Re: [s-cars] Digest Number 796

[Bernie Benz]

Kirby,  Apparently you haven't had, or don't remember an elementry course in
strength of materials, so with your ingulgance, I'll lead you through the
relevant aspects.  First, a column must be straight to resist reasonable
load.  Column failure results at some load at which the column becomes
unstable and buckling occurs, a catastrophic event.  Accepted column design
allows for a reasonable safety factor under this instability point.  By
definition, a column will not be unstable or, in this case, bend at the
design load.  My column design remains straight, as it is not loaded to even
the acceptable design limit, and is not subject to bend inducing end torques
because of the ball joint rod ends.

> From: Kirby Smith <kirby.a.smith at verizon.net>
> Reply-To: kirby.a.smith at verizon.net
> Date: Sun, 26 Aug 2001 16:41:50 -0400
> To: Bernie Benz <b.m.benz at prodigy.net>
> Cc: TM <t44tq at mindspring.com>, Greg Johnson <gregsj2 at home.com>,
> tommy.arnberg at nokia.com, 200q20V mailing list <200q20v at audifans.com>
> Subject: Re: [s-cars] Digest Number 796
> 
> Thanks Bernie:
> 
> However, I wasn't thinking of failure, but when the column is
> compressed, it will bow outwards slightly, in an indeterminate
> direction.  This will change the camber.  Now, I agree that the flexure
> of the top strut bearing rubber will be greater than the flex of the
> EMT, and therefore this is an improvement, but I would think you would
> want to minimize it.
> 
> My impression from what you wrote is that the force at the top of the
> strut is minimal, else I would think that your compression initial state
> would eventually go to zero at some cornering force.  Further, if in
> compression, then the strut bearing rubber is stressed into some
> attitude, then when the compression lessens, the rubber will unstress
> and the geometry changes.
> 
> Another possibility of not insignificant probability is that I don't
> understand the nature of the geometry, and forces never lets the effects
> above happen.
Right on, Kirby.  IMO, you just don't comprehend the geometery that we are
dealing with and are arguing qualitive suppositions.  I would prefer that
you either accept my design, or confront the design with a technically
substantial and logical argument.

Regards,

Bernie

> 
> kirby
> 
> Bernie Benz wrote:
>> 
>> Kirby, if you do a simple, max. transverse cornering force at the top of the
>> strut analysis, you will find that a column of 1/2" EMT is adequate for the
>> job.  Column failure will occur long before compression failure.
>> 
>> If you read the disclosure, you will realize that the brace is designed to
>> be always in compression, which has several functional advantages, besides
>> cost.  The alignment procedure must be adapted to insure that this be the
>> case.
>> 
>> Regards,
>> 
>> Bernie Benz
>> Gardnerville, NV
>> 
>> '90 90Q-20V  140K, w/Benz Brace
>> '91 200Q-20V 140K, w/Benz Brace
>> Ford "Quatro" Tractor
>> Other Misc. Toys
>>> From: Kirby Smith <kirby.a.smith at verizon.net>
>>> Reply-To: kirby.a.smith at verizon.net
>>> Date: Sun, 26 Aug 2001 13:56:42 -0400
>>> To: Greg Johnson <gregsj2 at home.com>
>>> Cc: s-car-list at yahoogroups.com, Russ Panneton <panneton at xilinx.com>, Bernie
>>> Benz <b.m.benz at prodigy.net>
>>> Subject: Re: [s-cars] Digest Number 796
>>> 
>>> This scheme might have flex in compression, so a stronger tube might be
>>> in order.  Also, the directions are unclear about how the heim-joint
>>> thread nut is attached to the bar.  It might be assumed the heim joint
>>> is just slid into it, which I doubt.
>>> 
>>> kirby
>>> 
>>> Greg Johnson wrote:
>>>> 
>>>> Russ,
>>>> 
>>>> This is what Bernie Benz did when he designed what we call the "Benz
>>>> Brace."
>>>> 
>>>> Bernie says:
>>>> 
>>>> "I developed the strut brace to correct the excessively negative static
>>>> camber condition of the 44 chassis.  It has
>>>> allowed my 5K and 200 to be aligned to exactly zero camber for street
>>>> purposes."
>>>> 
>>>> "But further, it minimizes dynamic camber changes caused by transverse
>>>> cornering forces far better than any tower brace, because it includes the
>>>> upper strut bushing deflections in the
>>>> equation.  Essentually, it ties the two upper strut tops together in an
>>>> infinitely stiff manner (relatively speaking) and thus, divides the upper
>>>> cornering force equally between the two
>>>> sides for a theoretically minimum transverse deflection."
>>>> 
>>>> If it works on a 200, it may fit on the urS4/S6s as well.
>>>> 
>>>> Details can be viewed at:
>>>> 
>>>> http://members.aol.com/c1j1miller/strutbrace.html
>>>> 
>>>> Greg J
>>>> BIRA.ORG
>>>> 
>>>>> Date: Sat, 25 Aug 2001 20:33:55 -0600
>>>>> From: "Russ Panneton" <panneton at xilinx.com>
>>>>> Subject: Re: Strengthening the car front between struts  A200 20V, S4 ?
>>>>> 
>>>>> How about putting the brace between the tops of the two front shocks?
>>>>> Have
>>>>> you ever noticed how much the upper strut mount allows the top of the
>>>>> strut
>>>>> to move around?  You can't just
>>>>> rigidly mount the top of the strut to the body or you'll probably get too
>>>>> much road noise and harshness.  But using a longer strut brace to tie the
>>>>> two shock tops together would
>>>>> maintain the noise isolation while effectively doubling the rigidity of
>>>>> the
>>>>> top mounts.
>>>>> 
>>>>> Russ.
>>>> 
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