A clip-on composite sensor based packaging design method for fiber Bragg grating axle counter

Purpose To address the encapsulation challenge of fiber Bragg grating (FBG) sensors in complex railway environments, this paper designs a clip-on composite sensor enabling installation-friendly deployment and long-term axle counting system monitoring. Design/methodology/approach Wheel–rail mechanical behavior was simulated via finite element analysis (FEA) to determine optimal sensor placement. A clip-on composite sensor was subsequently engineered. Stress transduction efficacy was validated through FEA quantification of stress responses at the axle counter location. Findings The proposed FBG axle counter integrates temperature compensation and anti-detachment monitoring as well as advantages such as simplified installation with minimal maintenance and sustained operational reliability. It effectively transmits stress, yielding a measured strain of 39 µe under static loading conditions without sensitivity-enhancing elements. Originality/value This study performs FEA of wheel-rail stress distribution and engineers the dual-slot composite sensor, FEA was conducted to quantify the stress magnitude at the axle sensor position of the dual-slot composite sensor. Additionally, FEA was performed on sensors with different structural configurations, including adjustments to the axle sensor position, number of slots and axle position. The results confirmed that the designed composite sensor exhibits superior stress transfer characteristics.