Experimental and Finite Element Study on Low‐Velocity Impact Response and Residual Strength of Multistitch BFRP‐T Joints

ABSTRACT In recent years, T‐shaped joints made from basalt fiber‐reinforced polymer composites (BFRP‐T) have been increasingly utilized as critical connection components in advanced engineering applications. However, these joints are prone to interfacial delamination and debonding under low‐velocity impact (LVI) loads, which can significantly reduce their residual tensile strength. To address this issue, this study introduces a stitching technique aimed at improving the interlaminar performance of BFRP‐T joints. A systematic investigation was carried out to evaluate the influence of stitching methods, thread fineness, number of stitched edges, and stitching pitch on both impact resistance and postimpact tensile residual strength. Scanning electron microscopy (SEM) observations demonstrated that the stitching technique effectively suppresses crack propagation by forming a bridging and anchoring effect at the thread‐resin interface, thereby facilitating longitudinal crack propagation. The presence of resin adhered to the fractured thread surface confirmed the synergistic deformation between the thread and matrix, indicating effective interlaminar load transfer during loading and elucidating the micromechanical mechanism through which stitching enhances interlaminar performance. This study confirms that the stitching technique can significantly improve the impact damage resistance and residual strength of BFRP‐T joints, providing valuable insights for the structural design optimization of composite connections in aerospace, marine, and transportation engineering applications.