The influence of equipment variations on sliotar–hurley impact in the Irish game of hurling
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The game of hurling is ranked as one of the fastest and most skilful field games in the world. It is played by a stick, hurley, made of ash wood and a ball, sliotar, made of a cork core or similar viscoelastic materials. Better standardisation of the game equipment requires analysing impacts to quantify precisely the effect of variations in equipment design on the resultant impact force at low and high striking speeds. Therefore, the purpose of the present study was to use a high-speed camera to (1) characterise the impact dynamics in term of impact force magnitude and duration, and (2) investigate whether a relationship exists between the game equipment and the magnitude of the impact force. An air cannon unit (ACU) test rig was set up to cause the sliotar to strike the hurley at predetermined speeds. A high-speed camera operating at 12,500 frames per second (fps) was used to capture 32 experimental impacts covering a range of sliotar and hurley brands, impact locations and impact speeds. The factor “sliotar brand” was identified as the most significant factor for the impact force among other main factors and two-factor interactions at a constant speed and it had a significant effect with up to 27 % difference between sliotar brands. It was demonstrated that, at higher impact speeds, the force–deformation curves of the sliotar brands varied significantly, even though similar force–deformation curves have been reported at quasi-static compression and similar COR values at low impact speeds using the standard free-drop test. This is the first known study to characterise the unique, highly non-linear and anisotropic sliotar–hurley impact using high-speed camera technology. It highlights the need for a tighter standard for sliotar materials and manufacturing to increase uniformity between different brands and strongly suggests that the standard free-drop test is not sufficient to characterise and compare game equipment.
KeywordsAnalysis High-speed camera Hurling ball Impact force DoE
The authors thank Mr Ger Rasmussen for data collection and technical advice and the support of the CIT Department of Mechanical Engineering in making the air cannon unit and Instron mechanical tester freely available. The authors would like to acknowledge the funding from the Institutes of Technology of Ireland Strand 3 research programme in the Smart Systems Integration Group project.
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