A two-part experimental study was conducted in order to better understand how the delivered face angle and club path of a golf club influences the initial launch direction of a golf ball for various club types. A robust understanding of how these parameters influence the ball direction has implications for both coaches and club designers. The first study used a large sample of golfers hitting shots with different clubs. Initial ball direction was measured with a Foresight Sports camera system, while club delivery parameters were recorded with a Vicon motion capture system. The second study used a golf robot and Vision Research camera to measure club and ball parameters. Results from these experiments show that the launch direction fell closer to face angle than club path. The percent toward the face angle ranged from 61% to 83%, where 100% designates a launch angle entirely toward the face angle.
Golf is played at a range of temperatures. The aim of this research was to determine the effect of temperature on golf ball dynamics. Normal impact testing at speeds up to 48 m·s-1 was conducted at ball temperatures of -0.8 °C, 22 °C and 35.9 °C. Golf balls were projected onto a fixed rigid surface and inbound and rebound velocity, impact duration and maximum deformation were measured using a high-speed video camera. Coefficients of restitution, impact durations and maximum deformations were found to increase with temperature. A finite element model of the golf ball was produced using Ansys/LS-Dyna and the dynamic response corresponding to each temperature was obtained by systematically adjusting the material properties of the core. Changing golf ball dynamics with temperature has implications on approval test procedures as well as the development of balls and clubs. This research is the first step in a process for determining the effect of temperature on a golf drive.
Golf is a sport which requires players to use ground interaction to generate clubhead speed in order to propel the ball towards the target. Force platforms are a technology which can be used to measure these ground reaction forces. Golfers generate force through a combination of jumping, sliding or twisting actions during the swing. Understanding how golfers generate these forces and if there are any groups which golfers could be clustered into could be used to enhance golf instruction as well as clubhead design or fitting practices for golf equipment. A total of 105 right-handed experienced golfers (handicap mean = 8.32 ± 8.31) consented to participate in the study of different swing speeds (31 below 95 mph, 41 over 105 mph and 33 between 95 and 105 mph). A calibrated single force plate was used for the test which sampled at 1000 Hz and recorded force and moment data in three axes. After a self-guided warm up, the players were instructed to hit five 7-iron shots and five drives to the best of their ability in an indoor hitting bay which used a launch monitor to record the club delivery and ball flight information. It was found that handicap or swing speed did not dictate the primary force production mechanism (sliding, jumping or twisting/spinning). This knowledge could aid engineers to design equipment better suited to the individual and help coaches build individualized programs to create power and clubhead speed in all players.
A thorough understanding of how the delivered face angle and club path of a golf club influences the initial launch direction of a golf ball can play a significant role in the design of various club types as well as help players and coaches better understand performance in the field. A theoretical model based on a Hertzian impact formulation with the inclusion of tangential compliance via Coulomb friction is compared to empirical results. This comparison demonstrates that the initial launch direction of a golf ball for a given club path and face angle can be sufficiently predicted by the theoretical model, providing insights into the mechanisms leading to different launch direction percentages relative to face angle for various club types. Additionally, the relationship between launch direction and the coefficient of friction is explored for various angles of incidence.