Study of hourglass-shaped specimens for the analysis of compression behaviour in fibre direction of FRP composites using compression and four-point bending tests

Flat hourglass specimens are proposed to assess the compressive behaviour of FRP utilizing two testing techniques. The hourglass shape helped to ensure failure at the centre of the specimen and to minimize in -plane stress concentration in this zone. Four-point bending tests are carried out and measures are performed via DIC. A procedure to calculate bending moment is proposed and validated in presence of large displacements. To evaluate the specimen and the method proposed, two different materials were tested, an E-glass/Epoxy unbalanced woven and a Carbon/PEEK balanced woven. In a second time ASTM D695 compression tests are carried out on the E-Glass/Epoxy composite to compare the hourglass specimens to the standardized dog-bone. The two testing techniques are analysed and compared.