Compressive transverse fracture behaviour of pultruded GFRP materials: Experimental study and numerical calibration

This paper presents a study on the transverse fracture behaviour of pultruded glass fibre reinforced polymer (GFRP) materials in compression, namely the assessment of transverse compressive fracture toughness (G(2)(-)) and transverse compressive residual strength (sigma(r)). These properties were assessed through experimental Compact Compression (CC) tests of six different GFRP materials, which were coupled with a data reduction method to determine experimental predictions of G(2)(-) and numerically calibrated as a function of the experimental load vs. displacement curves. Through this process, the expected experimental overestimation of G(2)(-), attributed to contact stresses behind the notch tip, was evaluated and accurate numerical estimates of G(2)(-) were determined. The numerical calibration considered both G(2)(-) and sr, by considering a bi-linear cohesive law. Through the numerical calibration, the G(2)(-) results ranged between 36 and 67 N/mm and sr values varied from 9% to 16% of transverse compressive strength (7.6 and 16.9 MPa, in absolute values). Finally, the G(2)(-) results were analysed as a function of transverse fibre reinforcement percentage and compared to transverse tensile fracture toughness results (G(2)(+)) determined in a previous work. This study showed that G(2)(-) is generally higher than G(2)(+) and that the compressive-to-tensile ratio is inversely proportional to the transverse reinforcement percentage.