The effect of mass distribution on cricket bat playing properties

Unlike most major sports, the game of cricket has seen little development in its implements based on modern technologies. It is likely that the first bat was an unfashioned branch from a tree and was used to defend against a suitably round stone in the games from which cricket evolved. Since this time, the design of the bat has been an intrinsic part of the games development, but these changes have been empirical and the effectiveness of the bat has relied upon the skill and knowledge of the bat maker and batsman. A significant part of this research project, supported by Dunlop Slazenger International, is to understand the science behind cricket bat performance. Golf club manufacturers have improved perceived 'feel' and measurable performance of golf club drivers by re-distributing the mass of a solid club head towards the outer surface, in the form of an aluminium or titanium 'shell like' structure. The improvement in performance is such that modern driver heads are predominantly hollow and this development has also occurred in contemporary baseball bat and tennis racket design. However, the benefits of a hollow implement construction have largely eluded cricket. This study has investigated the possible advantages of a hollow wooden cricket bat in comparison to a more conventional, solid design through the manufacture and testing of hollow bat prototypes. Experimental procedures have been developed to accompany this research in the measurement of bat weight distribution and impact performance testing. Prototypes of a multiple wood layer construction were modelled in a computer-aided design environment and realised using computer numerically controlled machining. Further work included the use of finite element analysis to simulate observed impacts between bat and ball and the definition of a bat grading system based upon player perception of bat mass properties. The research has shown that modification of bat playing properties can be achieved by the design of Internal geometry. The hollow bats manufactured in this study demonstrated significant changes in moments of inertia and impact properties in comparison to a solid bat of similar external shape and size. Considering the traditional nature of the game, the ability to generate a range of playing characteristics within the confines of a conventional external shape may be significant for future bat design.