Mechanical Characteristics of Golf Club Head-Shells Filled with High-Pressure Gas

Abstract

In order to increase flying distance of golf balls and to improve controllability of flying trajectory of golf balls, a lot of developments in materials and designing of golf clubs are being made. A new type of golf club head-shell made of titanium alloy filled with compressed nitrogen gas is proposed. In this paper, experimental investigations of three kinds are made on the static and dynamic deformation of the pressurized head-shells and also on the restitution of balls. First, the elastic and plastic changes of volume of head-shells are measured by static pressure tests. Capacity to resist pres sure is also determined. Next, the relationships among the impact velocity, pressure of gas, and velocity of golf ball are investigated. Finally, transient strain histories on the crown face and sole face of the head-shells are measured by strain gauges under impact. Effects of the pressurized gas on the transient deformation of the head-shells are discussed by means of the frequency analysis of strain histories. As a result, we found that all of the head-shells were deformed elastically in a pressure range between 0MPa and 2MPa and that plastic deformation occurred for higher pressures than 2 MPa. One of the head-shells was cracked at approximately 7.4MPa. When the head-shells were pressurized, the velocities of golf ball, the strain histories on the face of the head-shells, and the frequency spectra of the strain histories were changed slightly.