Shear Strength Setup

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#1

Hi Everybody

I need to test a sandwich laminate/coupons for shear stress. Has anybody some pictures or hints about a homemade test setup?

#2

There was a DIY test setup explained in an issue of Professional Boatbuilder. (www.proboat.com). Somewhere in issue 80-100 or so. Unfortunately I tossed all of them during my last move.

I am thinking about buying all back issues (available on USB)

#3

https://dl.dropbox.com/u/32251231/C393.pdf
https://dl.dropbox.com/u/32251231/C273.pdf

There are some sandwich shear ASTM tests, maybe that will help

#4

Thanks a lot for the pdfs.

According to this thesis one could test a laminate for shear in the same way one would test for tension with the only difference that the fibers should be aligned at ±45º. Would you say thats ok?
If i test a laminate without core for shear, I should afterwards select a core that has more shear strength that targeted.

#5

I can not say if that would work. I do not think that just by doing a tension test on 45deg samples, that would equal bending shear. You have to worry about the faces being in both tension and compression during a bend.

#6

You need to be more specific on which shear properties you are trying to measure: in-plane (xy plane), out-of-plane (xz or yz plane) where the x and y directions are your 0 and 90 fiber directions and the z direction is the thickness of the laminate. in-plane shear properties of a single skin laminate can be measured using the +/-45 tensile test.