Comparison of a finite element model of a tennis racket against simulated play

Tennis equipment manufactures should have a complete understanding of the physics of the game, as this aid will aid them when designing and developing the next generation of rackets, strings and balls. Finite element (FE) models have to be used previously to simulate impacts between a tennis ball and racket. The accuracy of these models is usually obtained by comparing them against experimental data obtained within a laboratory. The aim of this paper is to compare an FE model to a freely suspended racket against impact data from actual tennis shots. An FE model consisting of a tennis ball, string-bed and racket was constructed in Ansys/LS-DYNA 10.0. The FE model was compared with data for the impact of a ball on a racket for 18 actual tennis shots. The data for the tennis shots was collected from elite players during practice at the 2006 Wimbledon qualifying tournament. The root mean squared error for the rebound properties of the ball from the FE model and the actual shots was, 0.9 ms-1 for velocity, 9° for angle and 61 rad.s-1 for spin. It was concluded that the FE model is sufficiently accurate to replicate the impact between a ball and racket during an actual tennis shot. The FE model can now be used to determine the effect of changing equipment parameters, such as the structural stiffness of the racket frame.