Experimental and Numerical Investigation on the Dynamic Impact Response of Hat‐Shaped Basalt Fiber‐Reinforced Polymer Composite Structures With Improved Interfacial Properties

ABSTRACT Basalt fiber‐reinforced polymer (BFRP) composites are gaining attention as sustainable alternatives to conventional fiber‐reinforced polymers owing to their favorable mechanical properties and environmental advantages. However, their structural performance under dynamic loading remains insufficiently explored, particularly in geometrically complex configurations, due to the inherently low interlaminar strength of BFRPs. In this study, the dynamic impact behavior of a hat‐shaped BFRP composite structure was investigated using experimental testing and finite element analysis (FEA). A previously developed cellulose nanocrystal (CNC) surface treatment technique was applied to the BFRP to improve interfacial bonding and damage tolerance. This approach resulted in an increased energy absorption capacity and resistance to delamination compared with those of the unmodified BFRPs. Furthermore, the influence of span length (80, 140, and 200 mm) on failure mechanisms and energy absorption was analyzed. The results revealed a clear transition in failure modes from shear‐induced brittle failure at shorter spans to tensile‐dominated progressive failure at longer spans. The numerical analyses strongly agreed with the experimental results. This work provides novel insights into the span‐dependent and crashworthiness of BFRP composites and demonstrates their potential for use in lightweight and energy‐absorbing structures.