OF UNIDIRECTIONAL COMPOSITE COMPRESSION SPECIMEN THICKNESS AND
Xie and Donald F. Adams
combined numerical and experimental study was performed to investigate
the effect of both specimen thickness and loading method on
the compressive strength of a unidirectional fiber-reinforced
polymer composite. A three-dimensional finite element analysis
was used to study the stress distribution within a tabbed coupon
specimen. The compressive load can be applied directly on the
ends of the specimen, or be generated by longitudinal shear
forces on the tab surfaces. The end loading method was found
to be superior to the shear loading method, yielding a less
severe stress concentration at the tab termination points and
a similar stress concentration at the outer ends of the specimen.
For thick specimens this benefit is more obvious and therefore
a higher compressive strength should be obtained for a thick
specimen subjected to end loading. Hercules AS4/3501-6 unidirectional
carbon/epoxy composite specimens of various thicknesses were
tested using both ASTM D3410, Procedure B (shear loading) and
the Wyoming End-Loaded Side-Supported Test Method (end loading).
The experimental data were found to correlate very well with
the numerical predictions.