Measurement of hand loads and the centre of percussion of cricket bats

Abstract

Experimental procedures for the measurement of hand loads and the centre of percussion (COP) of cricket bats are described. Five commercial cricket bats were evaluated to demonstrate differences in static and dynamic performance characteristics. A standard bat was compared with three bats, incorporating different scallop shapes in the back of the bat and a fifth bat with two slots in the bat back containing honeycomb inserts. All the bats possessed the same external dimensions. Three clamping configurations were employed for measuring bat performance. Bat stiffness was measured using rigid mechanical clamps. Hand loads were measured with load transducers positioned in rigid clamps, in a hand simulator, and attached to the hands of human subjects. The COP for the five bats was measured in a hand simulator, which closely simulated hand loads. Bat and handle deflections for the five bats varied considerably, and in some instances, bat deflections were slightly non-linear. Hand loads were measured for one commercial bat subjected to ball impacts in rigidly clamped, simulator clamped and hand-held conditions. Simulator clamping closely mimicked the pattern of hand-held loads, but loads were approximately ten times higher in the hand simulator. The COPs for all five bats were evaluated by measuring loads in the hand simulator. A common COP located at 0.18 m from the bat end was deduced but simulated hand loads varied considerably. Bat geometry was seen to influence the static and dynamic responses of the five commercial bats.