If you guys have the materials? Why don't you just build a copuple of
test specimans and load them to destruction to see if there is any
difference in the load at failure.
Jim
On Sun, 24 Oct 2004 10:21:17 -0500 "Mark Langford" <n5...@hiwaay.net>
writes:
> > I tell ya Frank - if I could just get my mind around this
> dissimilar
> > stiffness thing. According to at least one reputable composite
> guy,
> > this is a problem. I am sure there is an answer /solution, but in
> the
> > mean while it really worries me.
>
> I'm not sure exactly what the previous paragraph is about, but I do
> remember
> the subject of carbon fiber in spars came up a few weeks ago, and it
> says
> something to the WAF question asked earlier.
>
> >From AN-18, paragraph 4.82, Behavior of Dissimilar Materials
> Working
> Together:
> "When materials of different rigidities, such as normal wood,
> compreg, or
> metal fittings, are fastened together for a considerable distance
> and are
> under high stress, consideration should be given to the fact that
> the
> fastening causes the total deformation of all materials to be the
> same. A
> typical example is a long metal strap bolted to a wood spar flange
> for the
> purpose of taking the load at the wing joint. In order that the
> load be
> uniformly distributed among the bolts, the ratio of the stress to
> the
> modulus of elacticity should be the same for both materials at every
> point.
> This may be approximated in practical structures by tapering the
> straps and
> the wood in a such a manner that the average stress in each (over
> the length
> of the fastening) divided by its modulus of elasticity gives the
> same
> ratio."
>
> Of course, fastened joint design is also a large consideration in
> the case
> of WAFs. I am certainly not an expert on this sort of thing, but
> I'm sure
> the information is out there somewhere if somebody wants to do the
> homework.
> I probably even have that sort of thing in my personal collection
> of
> aircraft design stuff, but right now I want to finish up my plane.
> The time
> for design and testing is long over for THIS airplane...I just need
> to get
> N56ML flying. Yesterday I finished up the tailwheel and rudder
> cables, and
> will do shoulder belts today. The seat is now lowered, and canopy
> latches
> are in the works, so my list of excuses is on the decline. My list
> of 30
> things that needed to be done is now down to "only" 24, so there's
> still a
> ways to go, but things should be slowing down a little at work soon,
> so
> maybe I'll actually get to finish it soon. I should be very close
> to
> taxiing around the neighborhood, and blowing the leaves out of the
> yard...
>
> Mark Langford, Huntsville, Alabama
> N56ML "at" hiwaay.net
> see KR2S project at http://home.hiwaay.net/~langford
>
>
>
> _______________________________________
> to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net
> please see other KRnet info at http://www.krnet.org/info.html
>
>
