Modelling and simulation of the coefficient of restitution of the sliotar in hurling

Abstract

The coefficient of restitution (COR) is one of the most important standards in all bat-and-ball sports to study the ball suitability and bouncing characteristics. Currently, a demand exists for an improved analytical model for computing the COR, particularly when a new material is introduced. A viscoelastic ball known as a sliotar is taken from the Irish bat-and-ball sport of hurling and used in this paper as a case study. For the theoretical approach, a modified Maxwell's viscoelastic model was used to derive an analytical formula to predict the COR. The developed formula confirms that the damping ratio and the dependency of the COR on the impact speed are the most dominant factors. A 3-dimensional finite element (FE) model was developed to simulate the sliotar impact test to estimate the COR, and to provide a simple tool for further studies on the sliotar. A high-speed camera was used to film the impact event to validate the models' behavior. The close correlation of 9% and 5% between the experimental and the developed analytical and FE models, respectively, indicates that the developed models can successfully identify the COR of the ball in the game of hurling and similar bat-and-ball sports.

Estudo Numérico Do Efeito Das Propriedades Das Partículas E Da Velocidade De Impacto Sobre O Coeficiente De Restituição

“…A partir dos dados das velocidades de impacto e de rebatimento, os coeficientes de restituição foram calculados segundo a Equação 1. As velocidades de impacto foram também empregadas para o cálculo de e a partir da correlação proposta por Alsakarneh et al (2012), conforme a Equação 2.…”

“…A correlação proposta por Alsakarneh et al (2012) é derivada do modelo viscoelástico de Maxwell modificado, adaptado para esferas rígidas (módulo de Young = 6,7 x 10 7 Pa).…”

“…Comparando os dados de e simulado e e correlação para as esferas de ABS, observam-se baixos desvios (entre 1,6% e 3%), o que indica que a correlação proposta por Alsakarneh et al (2012) foi capaz de prever de forma satisfatória o coeficiente de restituição dessas partículas. No entanto, desvios superiores a 70% para as esferas de tapioca demonstram que o modelo teórico não é adequado para descrever o coeficiente de restituição de partículas macias.…”

“…A correlação proposta por Alsakarneh et al (2012) forneceu resultados satisfatórios para as esferas de ABS, mostrando-se adequada para descrever o comportamento de colisões de partículas rígidas, com maior módulo de Young.…”

Numerical modelling and optimization of an electronic system embedded in multi-layered viscoelastic materials under shock loads

“…The third constraint was the CoR, the CoR is computed as following: the ball should be dropped freely from 1.80 m onto a concrete base and the rebound height isCoR = �rebound height/drop height.detail of free-drop test and simulation is described by an earlier work[16]. The original ball COR was 0.56 after dropping of l.8 m height in comparison to 0.49 CoR of the modified ball.…”