Characterizing pseudo-ductile behavior of pultruded and pullwound GFRP composites: Box-section short columns subjected to axial compression

GFRP composites are known to suffer from the “sudden-brittle failure”, while this work demonstrates a different behavior, namely pseudo-ductile behavior. A total of 28 pultruded and pullwound GFRP composite short columns having two heights were tested in axial compression. Stable pseudo-ductile behavior was observed in all tests, and it was realized by the progressive failure of GFRP composites. The residual strength of GFRP columns could be maintained at a high stress level, ranging from 50 % to 83 %. In order to quantify the pseudo-ductile behavior, FE model was developed within Abaqus, and a VUMAT subroutine incorporated with 3D Hashin damage criterion was used to predict the progressive failure of materials. Developed FE model was able to satisfactorily simulate the entire progressive failure process of pultruded and pullwound GFRP short columns. As a result, predicted peak strengths showed excellent agreement with experimental results, with average strength ratio of 1.00 (COV = 0.04), and the predicted residual strengths at the deformations of interest were generally conservative, with average strength ratio of 0.85 (COV = 0.24). The experimental and numerical results obtained in this work successfully show that pultruded and pullwound GFRP short columns could exhibit stable progressive failure at a high stress level. The finding is aimed to shed light on the future acknowledgement of the pseudo-ductile behavior as well as to promote the performance-based design of GFRP composite structures.