Composite Structures 327 (2024) 117660 Available online 29 October 2023 0263-8223/© 2023 Elsevier Ltd. All rights reserved. Stability analysis of pultruded basalt fber-reinforced polymer (BFRP) tube under axial compression Yu Chen a, b , Chuntao Zhang a, b, c, * a Shock and Vibration of Engineering Materials and Structures Key Laboratory of Sichuan Province, Mianyang 621010, PR China b School of Civil Engineering and Architecture, Southwest University of Science and Technology, Mianyang 621010, PR China c Department of Mechanical Engineering, University of Houston, Houston 77054, United States A R T I C L E INFO Keywords: Basalt fber-reinforced polymer (BFRP) tube Axial compressive properties Stress–strain model Load–lateral defection model Stability Buckling ABSTRACT This study analyzed mechanical properties and stability of pultruded basalt fber-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 defection 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 experi- ments. The predictions derived from proposed models were consistent with experiment results. 1. Introduction Fiber-reinforced polymer (FRP) composites have been widely recognized as effective structural reinforcing materials in civil, envi- ronmental, energy, and aerospace engineering owing to their superior physical, mechanical, and chemical properties compared to conven- tional steel reinforcement [1,2]. In addition to structural reinforcement, FRP profles, such as tubes or H-shapes, can also be used in trusses to create lightweight and durable structures. Although some high-strength steels have good weathering and corrosion resistance [3–7], fber- reinforced composite materials have higher strength and are lighter. Under similar conditions, FRP can reduce application costs and increase service life [8,9]. In addition, FRP bridge elements are easily produced, transported, and installed and require minimal maintenance [10,11]. As a result, using fber-reinforced polymer (FRP) composites as substitutes for steel members in large-span spaces and truss structures has gained substantial research attention. Large-span spatial and truss structures employ multiple mechani- cally instable axially-compressed rods, rendering these structures sus- ceptible to failure [12–14]. To satisfy the mechanical property requirements of these application scenes, glass fber-reinforced polymer (GFRP) pipes were widely utilized since they possess high compressive strengths of 200 to 300 MPa and elastic modulus of approximately 30 GPa [15–17]. Moreover, establishing a criterion to differentiate the compressive behaviors of short and long FRP composites is necessary for avoiding overall instability and fatal consequences [18]. Several factors, such as the initial curvature, initial eccentricity, material imperfections, and residual stresses may reduce the load-carrying capacity of FRP composites. Nevertheless, the stiffness of FRP composites is a critical design criterion for compression elements. The high strength-to-weight ratio of GFRP makes it a feasible ma- terial for large-span spaces and truss structures. However, long-term use of GFRP can result in creep, leading to large deformations under service loads. Although carbon fber-reinforced polymer (CFRP) is a viable alternative to GFRP, its high cost limited its use in residential buildings [19,20]. Recently, basalt fber has been proven to be a promising ma- terial due to its excellent mechanical strength, sound insulation, and thermal insulation. Previous studies have shown that basalt fber- reinforced polymer (BFRP) could be a suitable substitute for GFRP in truss structures [21] owing to its 30 % higher strength and modulus, * Corresponding author. E-mail address: chuntaozhang@swust.edu.cn (C. Zhang). Contents lists available at ScienceDirect Composite Structures journal homepage: www.elsevier.com/locate/compstruct https://doi.org/10.1016/j.compstruct.2023.117660 Received 17 May 2023; Received in revised form 1 September 2023; Accepted 26 October 2023