Fracture Mechanisms of Composite Baseball Bats: Post-Diagnostic Insights

This study examined degradation in composite baseball bats from game and practice use. Techniques including X-ray diffraction, Raman spectroscopy, optical imaging, SEM, and EDX revealed microstructural changes: repeated impacts caused resin microcracks, fiber breakage, and delamination, progressively reducing performance. Carbon fibers showed amorphous/partially ordered structures, with high-stress regions initiating cracks. Elemental analysis identified carbon, oxygen, and nitrogen as primary components, with silicon/sodium traces from glass fibers. Key durability factors include tensile strength, fiber alignment, interfacial integrity, and laminate architecture. These findings underscore the necessity of optimized material selection and structural design to extend bat service life while maintaining performance.