Whilst tennis racket technology has progressed significantly over the last hundred years,
ball design has remained essentially unchanged. Concerns over falling interest in the
sport from both players and spectators require manufacturers to be able to engineer new
ball products for a wider range of playing styles and surfaces. Unfortunately, little
scientific knowledge exists on the effects of ball construction upon playing
characteristics, particularly how the ball behaves during the impact.
Finite element analysis provides the perfect environment in which to construct complex
models and interactions such as those present during a tennis ball impact. A
representative set of pre-impact conditions corresponding to a range of tennis shots was
selected. Various ball mesh geometries were created and a suitable set of material
properties was used to develop models for uncovered rubber cores and pressurised and
pressureless balls. Post impact characteristics of velocity, angle and spin were measured experimentally
using high speed digital image capture techniques, together with measurements of
impact force and local deformation using laser vibrometry. These results were used to
verifY that the material properties used were appropriate for the strain rates present. The
resulting models closely matched the experimental data.
The data input file was constructed in such a way that model parameters can be easily
altered by a user, providing a powerful design tool. Furthermore, the ball model may be
modified with simple manipulation so that it may be generically applied to represent any
hollow sports ball.
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.