Comparison of static and dynamic carbon fibre composite golf club shaft properties and their dependence on structure

• Main Author: Huntley, Matthew Philip
• Published: University of Birmingham 2006
• Subjects: 796.352
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.633199

Commercially available golf club shafts have been characterised for a range of quantifiable properties, including static and torsional stiffness, frequency along the shaft length and around the circumference, shaft diameter and wall thickness taper, 3- point mini-beam bend testing, and microstructure. The frequency of the shafts tested ranged from 230 to 268 cpm (cycles per minute) and was shown to vary by up to 5 % around the individual shaft circumferences, with the stiffness varying along the shaft length depending on the dimensional profile. The wall thickness was also shown to vary around the shaft circumference by up to 27 % and correlation was found between increases in the shaft stiffness and increases in wall thickness for individual shafts. The variations in wall thickness, however, were unable to totally describe the stiffness variations around the circumference of the shafts. Variations in microstructure, in particular fibre volume fraction, which could cause up to a 9 cpm change in frequency were shown to exist throughout the wall thickness around the circumference of the shaft and were found to be influential on the shaft behaviour. The causes of stiffness variation have been prioritised. The dynamic stiffness of the shafts was measured and found to be approximately the same as the static stiffness for all of the sheet laminated shafts and approximately 12 % higher for a filament wound shaft due to the extra resin present. There was no statistical difference in measured stiffness between the orientations of high and low static stiffness when the shafts were tested dynamically.