Stability analysis of pultruded basalt fiber-reinforced polymer (BFRP) tube under axial compression.

• Axial compression behaviour of BFRP tubes with three different cross-sections was studied. • The stress–strain curves of the BFRP tubes was classified into three stages of elastic, elastic–plastic, and plastic. • Three types of compressive failure modes were observed in the BFRP tubes. • Two design-oriented three-stage theoretical models were proposed for BFRP tubes with different cross-sections. • A stability equation was derived for predicting the compressive strength of slender BFRP tubes. This study analyzed mechanical properties and stability of pultruded basalt fiber-reinforced polymer (BFRP) tubes under compressive axial loading for large-span space and truss structures applications. This study assessed the compressive strength of BFRP tubes with three different cross-sectional shapes and investigated the failure modes under compression with slenderness ratios ranging from 20 to 150. The results demonstrated that short BFRP tubes can achieve a compressive strength of up to 122.36 MPa with a compressive elastic modulus of 40.39 GPa. Three types of compressive failure modes were observed in the BFRP tubes, including local material, critical, and overall buckling failures. Furthermore, based on the analysis of experiment results, two design-oriented three-stage theoretical models were proposed for BFRP tubes with three different cross-sectional shapes. The proposed models were able to predict both the stress–strain and load-lateral deflection curves by taking into account the post-peak softening behavior of the stress–strain curve. In addition, a stability equation was also derived for predicting the compressive strength of slender BFRP tubes and was validated by experiments. The predictions derived from proposed models were consistent with experiment results. [ABSTRACT FROM AUTHOR]