Evaluation of the mechanical performance of golf shafts

Major mechanical properties of the golf shafts are experimentally and numerically evaluated. Experimentally, the deflection is measured by hanging a mass on the tip with the butt fixed. The degree of torsion is measured by applying the twisting moment, 13.72 (kgf cm), to the tip. The frequency of vibration is measured by adding a mass to the tip of a shaft and shaking it. The position of the kick point, that is, the maximum deflection point is measured by compressing the tip.The composite structure of a golf shaft made of fiber-reinforced plastics is modeled and the mechanical performance of the structure is numerically evaluated. Both a linear static and dynamic analysis for a golf shaft have been performed. Comparing the present numerical results with experimental data, the effects of major parameters on the performance of golf shafts are also discussed.The finite element results for deflection, degree of torsion, frequency of vibration, and position of kick point of golf club shafts converge very rapidly. The present simulation gives satisfactory results within a few percent of error compared with the experimental data. The numerical results show that the major parameters of golf shafts are strongly dependent on the material properties of fibers and design pattern. The present results will be useful in designing sheet-rolled golf shafts.