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The dynamic testing of soccer balls

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thesis
posted on 27.11.2013, 12:15 authored by Paul J. Neilson
Football, or soccer, is the most popular game 111 the world. The Federation Internationale de Football Association (FIFA) estimate that there are 247 million people currently involved in soccer throughout the world. In 1996 the world governing body of soccer, FIFA, launched the Denominations program to ensure the global consistency of top match soccer balls. Under the Denominations test program, a sample of balls undergo a series of testing procedures designed to ensure the manufacturing consistency of competition balls and inform the players of ball quality. The existing test procedures provide an adequate method for the assessment of ball manufacturing quality; yet do not provide any criteria for the assessment of dynamic ball performance. This study is concerned with improving the existing testing procedures, and developing new dynamic test procedures and instruruentation. A study of elite (professional) player kicking performance was undertaken to provide data on ball launch characteristics which could then be used as a benchmark for test development. An improved method of soccer ball sphericity measurement was devised using a coordinate measuring machine that provided an entirely automated method not subject to human error and interpretation. A method of measuring out-of-balance forces within soccer balls was developed using a vertical balancing machine and the magnitude and position of out of balance forces was assessed for a range of soccer balls. The effect of out of balance forces on dynamic ball performance was assessed in two studies. The initial ball flight characteristics and trajectories of soccer balls were investigated using a pneumatic kicking leg as a launch platform. It was shown that the magnitude and position of unbalance at impact have a significant effect on ball launch trajectory. A second study waS undertaken to assess the ability of professional players to perceive unbalance within soccer balls, although no significant results were obtained. The ball performance studies identified the need for an automated system for the analysis of soccer ball flight characteristics. Consequently, an automated image analysis system for the measurement of soccer ball launch characteristics was developed. The system is capable of measuring ball velocity, elevation, spin rate and spin axis to a high degree of accuracy.

History

School

  • Mechanical, Electrical and Manufacturing Engineering

Publisher

© Paul Neilson

Publication date

2003

Notes

A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University

Language

en