Characterization of thick glass woven roving/polyester laminates: 1. Tension, compression and shear

Experimental investigations of high strain glass/polyester woven fabric reinforced composites cut from 10 and 25 mm thick laminates were carried out in tension, compression, and in-plane and interlaminar shear. The conventional tensile tests were conducted using straight-sided coupon specimens with strain gauges on both the uncut and cut surfaces. The failure mode after significant non-linear behaviour was dominated by interfacial debonding, delamination and eventually fibre fracture. The properties in the 0° direction were found to be considerably greater than those in the 90° direction due to the larger number of fibres at 0°. The compressive tests were performed using a recently developed ICSTM method with strain gauges on both surfaces: their strengths were much lower than the tensile ones, whereas their moduli were fractionally higher than the tensile counterparts. Their failure mode was shearing with a kink band. The in-plane shear using the ± 45° tensile test was characterized by significant non-linearity enhanced by shear-tension coupling. The interlaminar shear (ILS) tests were carried out using the short beam shear method for both 10 and 25 mm thick beams. For the 10 mm beam the behaviour was found to be critically dependent on the support span-to-depth ratio, and a reasonable strategy was selected for choosing the correct ratio. The scale effect on ILS strength was observed to be very small.