Recommendations on important dimensions are provided for typical material configurations in
Table 2. These dimensions have been found by a number of
testing laboratories to produce acceptable failure modes on a
wide variety of material systems, but use of them does not
guarantee success for every existing or future material system.
The selection of a tab configuration that can successfully
produce a gage section tensile failure is dependent upon the
coupon material, coupon ply orientation, and the type of grips
being used. When pressure-operated nonwedge grips are used
with care, squared-off 90° tabs have been used successfully.
Wedge-operated grips have been used most successfully with
tabs having low bevel angles (7 to 10°) and a feathered smooth
transition into the coupon. For alignment purposes, it is
essential that the tabs be of matched thickness
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