-I feel the experiment should be done over a frame so that the edges are supported. This way it approximates more the hitting of a hard object by the hull.
Form what I have read, polyprop honeycomb comes out especially well under this test.
-- In harryproa@yahoogrou
>
> Hit it until it fails, not until the core has turned to dust! ;-) With the
> block of wood, assuming the blows were in the centre of the block (no edge
> loads), it may take 10 blows. With just the hammer, perhaps a series of
> blows of increasing force.
>
> Regardless, what you want is a comparison, not an absolute number. So start
> laminating the panels with the other cores.
>
> regards,
>
> rob
>
> On Mon, Jun 8, 2009 at 11:19 AM, Gardner Pomper <gardner@...
>
> >
> >
> > Oops!
> >
> > When you said, hit with a hammer, and put a block of wood and hit with a
> > sledgehammer, maybe I should have asked what you meant. Did you mean just
> > hit it once?
> >
> > - Gardner
> >
> > On Sun, Jun 7, 2009 at 11:09 PM, Rob Denney <harryproa@.
> >
> >>
> >>
> >> G'day,
> >>
> >> That is a pretty severe test! To make it usable, you need to do the same
> >> tests on the same laminate with different foam.
> >>
> >> If it breaks the same way, then you need to reduce the size or number of
> >> impacts on each until only one fails. Then continue the loads on the other
> >> until it also fails. This will give you a comparison.
> >>
> >> regards,
> >>
> >> Rob
> >>
> >>
> >> On Mon, Jun 8, 2009 at 10:54 AM, Gardner Pomper <gardner@...
> >>
> >>>
> >>>
> >>> Hi all,
> >>>
> >>> I took a couple of Rob Denney's testing suggestions and did them on a 1"
> >>> 1'x2' panel of 6lb Aircell. Here are the tests and the results:
> >>>
> >>> 1) Took a hammer and hit the panel as hard as I could, 10 times in one
> >>> spot
> >>>
> >>> 2) Took a 2x4 piece about 6" long, put it on the panel, then hit it with
> >>> a hand sledge 10 times, very hard
> >>>
> >>> After this, I cut the panel through each area.
> >>>
> >>> The hammer test broke the fiberglass (1 layer of 18oz biaxial, infused
> >>> with epoxy), dented the foam and delaminated the fiberglass around the area.
> >>>
> >>> The sledge test slightly dented the foam and delaminated the reverse side
> >>> of the panel.
> >>>
> >>> I have uploaded photos to the "Aircell Testing" album on the harryproa
> >>> yahoo group, under the Photos section, for anyone who wants to take a look.
> >>>
> >>> Obviously, the panel failed these tests. My question is, was I fair, or
> >>> was I too severe? Should I have only hit the panel once, instead of 10 times
> >>> each? Should I not hit it as hard as I could?
> >>>
> >>> - Gardner
> >>> York, PA
> >>>
> >>>
> >>
> >
> >
>
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