Compressive Properties of Pultruded Composites

The compressive properties of E-glass fiber/polyester resin matrix pultruded composites were measured using a short-block compression test fixture. Twenty specimens were tested in the pultrusion (longitudinal) direction and twenty more specimens in the transverse direction. Six specimens were tested at 30, 45, and 60° orientations to the pultrusion direction. Compressive properties such as the compressive modulus, compressive strength, Poisson ratio, and compressive failure strain were measured for both 6.3 and 12.7 mm thick pultruded sheet materials. The test specimens were rectangular with a length of 44.4 mm, width of 25.4 mm, and gage length of 25.4 mm. The test fixture was initially validated by measuring the axial strain distribution across the width of the specimen; from the beginning of loading up to the final failure, the distribution of strains across the specimen width was found to be very uniform. Back-to-back strain gages were also mounted on representative specimens. The end shortening was also measured on all specimens. The compressive strength data were analyzed both for the longitudinal and transverse directions using a two-parameter Weibull, lognormal, and normal distributions. The compressive properties are presented as functions of the specimen orientation angle for both thicknesses.