There was a post above that cited the composite expert at Boeing as stating the test method that produces the highest strength reading on composites in compression is the right one. The reasoning behind this is that compression testing is tough to get good results on - lots of ways to trip low readings that would then drive overbuild.
ok got it. This is exactly why I feel pure compression or shear readings or in general coupon tests are of limited value in composite design. If weight optimization is the goal then testing the actual article or a geometrically scaled one is the only rational way to proceed in my view.