Special Issue "Sports Materials"

A special issue of Applied Sciences (ISSN 2076-3417). This special issue belongs to the section "Materials".

Deadline for manuscript submissions: closed (31 October 2018).

Special Issue Editors

Dr. Thomas Allen
E-Mail Website
Guest Editor
Sports Engineering Research Team, Manchester Metropolitan University, Manchester M15 6BH, UK
Interests: sports engineering; finite element analysis; material characterization; experimental mechanics; sports injury prevention; sports equipment design; auxetic materials
Special Issues and Collections in MDPI journals
Dr. Leon Foster
E-Mail Website
Guest Editor
Centre for Sports Engineering Research, Sheffield Hallam University, Sheffield S10 2BP, UK
Interests: Material testing, performance modelling, Auxetic materials, Mechanical engineering
Special Issues and Collections in MDPI journals
Dr. Martin Strangwood
E-Mail Website
Guest Editor
School of Metallurgy and Materials, The University of Birmingham, Edgbaston Birmingham B15 2TT, UK
Interests: microstructure-processing-property relationships; strain rate dependence of properties; modeling of materials; characterization
Dr. James Webster
E-Mail
Guest Editor
Under Armour Inc, Baltimore 21230, UK
Interests: material testing; advanced manufacturing; material development; apparel; footwear; accessories; PPE
Special Issues and Collections in MDPI journals

Special Issue Information

Dear Colleagues,

The world of sport is dominated by materials; they are a key component of every piece of sports equipment, each modern playing surface, as well as clothing, footwear, and safety devices. History has shown that advances in materials have usually gone hand in hand with noticeable performance improvements. Any change or introduction of new materials into elite sport must be closely governed as not to cause too-drastic performance increases and/or be detrimental to the spectacle of the sport. Materials are also making sport and recreational activities safer by improving the performance of safety devices and personal protective equipment (PPE). Along with all these developments, new manufacturing processes and the use of new types of materials have brought down the costs of equipment and making certain sports more accessible to more people.

This Special Issue on "Sports Materials" is dedicated to recent advances in research and development of materials, equipment design, surfaces, apparel and the human body in relation to sport and physical activity. We invite you to submit research articles or reviews on the latest research work in these areas, with emphasis on applications in all areas of science and engineering.

Dr. Thomas Allen
Dr. Leon Foster
Dr. Martin Strangwood
Dr. James Webster
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Applied Sciences is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1500 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Instrumentation

  • Testing

  • Performance

  • Protection

  • Modelling

  • Finite element analysis

  • Composite

  • Polymer

  • Equipment

  • Impact

Published Papers (11 papers)

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Editorial

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Open AccessEditorial
Sports Materials Special Issue Editorial
Appl. Sci. 2019, 9(24), 5272; https://doi.org/10.3390/app9245272 - 04 Dec 2019
Abstract
Materials are key to the world of sport [...] Full article
(This article belongs to the Special Issue Sports Materials)

Research

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Open AccessArticle
A Finite Element Investigation into the Effect of Slope of Grain on Wood Baseball Bat Durability
Appl. Sci. 2019, 9(18), 3733; https://doi.org/10.3390/app9183733 - 07 Sep 2019
Cited by 1
Abstract
Bat durability is defined as the relative bat/ball speed that results in bat breakage, i.e., the higher the speed required to initiate bat cracking, the better the durability. In 2008, Major League Baseball added a regulation to the Wooden Baseball Bat Standards concerning [...] Read more.
Bat durability is defined as the relative bat/ball speed that results in bat breakage, i.e., the higher the speed required to initiate bat cracking, the better the durability. In 2008, Major League Baseball added a regulation to the Wooden Baseball Bat Standards concerning Slope-of-Grain (SoG), defined to be the angle of the grain of the wood in the bat with respect to a line parallel to the longitudinal axis of the bat, as part of an overall strategy to reverse what was perceived to be an increasing rate of wood bats breaking into multiple pieces during games. The combination of a set of regulations concerning wood density, prescribed hitting surface, and SoG led to a 30% reduction in the rate of multi-piece failures. In an effort to develop a fundamental understanding of how changes in the SoG impact the resulting bat durability, a popular professional bat profile was examined using the finite element method in a parametric study to quantify the relationship between SoG and bat durability. The parametric study was completed for a span of combinations of wood SoGs, wood species (ash, maple, and yellow birch), inside-pitch and outside-pitch impact locations, and bat/ball impact speeds ranging from 90 to 180 mph (145 to 290 kph). The *MAT_WOOD (MAT_143) material model in LS-DYNA was used for implementing the wood material behavior in the finite element models. A strain-to-failure criterion was also used in the *MAT_ADD_EROSION option to capture the initiation point and subsequent crack propagation as the wood breaks. Differences among the durability responses of the three wood species are presented and discussed. Maple is concluded to be the most likely of the three wood species to result in a Multi-Piece Failure. The finite element models show that while a 0°-SoG bat is not necessarily the most durable configuration, it is the most versatile with respect to bat durability. This study is the first comprehensive numerical investigation as to the relationship between SoG and bat durability. Before this numerical study, only limited empirical data from bats broken during games were available to imply a qualitative relationship between SoG and bat durability. This novel study can serve as the basis for developing future parametric studies using finite element modeling to explore a large set of bat profiles and thereby to develop a deeper fundamental understanding of the relationship among bat profile, wood species, wood SoG, wood density, and on-field durability. Full article
(This article belongs to the Special Issue Sports Materials)
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Open AccessArticle
Table Tennis Ball Impacting Racket Polymeric Coatings: Experiments and Modeling of Key Performance Metrics
Appl. Sci. 2019, 9(1), 158; https://doi.org/10.3390/app9010158 - 04 Jan 2019
Cited by 2
Abstract
The performance of a table tennis racket is often associated with subjective or quantitative criteria such as the adhesion, the control and the speed. Overall, the so-called performance aims at characterizing the impact with the ball. Ultimately, the polymeric layers glued onto the [...] Read more.
The performance of a table tennis racket is often associated with subjective or quantitative criteria such as the adhesion, the control and the speed. Overall, the so-called performance aims at characterizing the impact with the ball. Ultimately, the polymeric layers glued onto the wooden blade play a key role, as evidenced in a previous work where the normal linear (no spin) impact of a ball onto polymeric layers was experimentally and numerically investigated. In this work, more realistic loading conditions leading to varying the incident angle and spin of the ball, were explored. While the sole linear restitution coefficient was determined in the anterior normal impact study, new physical metrics were identified to describe fully the trajectory of the reflected ball after impact. A companion 3D finite elements model was developed where the polymeric time-dependent dissipative compliant behavior measured with dynamic mechanical analysis and compression tests was accounted for. The confrontations with the experimental data highlighted the key role of the polymer intrinsic properties along with the friction coefficient between the ball and the polymer external layer. Full article
(This article belongs to the Special Issue Sports Materials)
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Open AccessArticle
Characterization of Maple and Ash Material Properties for the Finite Element Modeling of Wood Baseball Bats
Appl. Sci. 2018, 8(11), 2256; https://doi.org/10.3390/app8112256 - 15 Nov 2018
Cited by 4
Abstract
To assist in developing a database of wood material properties for the finite element modeling of wood baseball bats, Charpy impact testing at strain rates comparable to those that a wood bat experiences during a bat/ball collision is completed to characterize the failure [...] Read more.
To assist in developing a database of wood material properties for the finite element modeling of wood baseball bats, Charpy impact testing at strain rates comparable to those that a wood bat experiences during a bat/ball collision is completed to characterize the failure energy and strain-to-failure as a function of density and slope-of-grain (SoG) for northern white ash (Fraxinus americana) and sugar maple (Acer saccharum). Un-notched Charpy test specimens made from billets of ash and maple that span the range of densities and SoGs that are approved for making professional baseball bats are impacted on either the edge grain or face grain. High-speed video is used to capture each test event and image analysis techniques are used to determine the strain-to-failure for each test. Strain-to-failure as a function of density relations are derived and these relations are used to calculate inputs to the *MAT_WOOD (Material Model 143) and *MAT_EROSION material options in LS-DYNA for the subsequent finite element modeling of the ash and maple Charpy Impact tests and for a maple bat/ball impact. The Charpy test data show that the strain-to-failure increases with increasing density for maple but the strain-to-failure remains essentially constant over the range of densities considered in this study for ash. The flat response of the ash data suggests that ash-bat durability is less sensitive to wood density than maple-bat durability. The available SoG results suggest that density has a greater effect on the impact failure properties of the wood than SoG. However, once the wood begins to fracture, SoG plays a large role in the direction of crack propagation of the wood, thereby determining if the shape of the pieces breaking away from the bat are fairly blunt or spear-like. The finite element modeling results for the Charpy and bat/ball impacts show good correlation with the experimental data. Full article
(This article belongs to the Special Issue Sports Materials)
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Open AccessArticle
Low-Velocity Impacts on a Polymeric Foam for the Passive Safety Improvement of Sports Fields: Meshless Approach and Experimental Validation
Appl. Sci. 2018, 8(7), 1174; https://doi.org/10.3390/app8071174 - 18 Jul 2018
Cited by 1
Abstract
Over the past few years, foam materials have been increasingly used in the passive safety of sport fields, to mitigate the risk of crash injury. Currently, the passive safety certification process of these materials represents an expensive and time-consuming task, since a considerable [...] Read more.
Over the past few years, foam materials have been increasingly used in the passive safety of sport fields, to mitigate the risk of crash injury. Currently, the passive safety certification process of these materials represents an expensive and time-consuming task, since a considerable number of impact tests on material samples have to be carried out by an ad hoc testing apparatus. To overcome this difficulty and speed up the design process of new protective devices, a virtual model for the low-velocity impact behaviour of foam protective mats is needed. In this study a modelling approach based on the mesh-free Element Galerkin method was developed to investigate the impact behaviour of ethylene-vinyl acetate (EVA) foam protective mats. The main advantage of this novel technique is that the difficulties related to the computational mesh distortion and caused by the large deformation of the foam material are avoided and a good accuracy is achieved at a relatively low computational cost. The numerical model was validated statistically by comparing numerical and experimental acceleration data acquired during a series of impact events on EVA foam mats of various thicknesses. The findings of this study are useful for the design and improvement of foam protective devices and allow for optimizing sports fields’ facilities by reducing head injury risk by a reliable computational method. Full article
(This article belongs to the Special Issue Sports Materials)
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Open AccessFeature PaperArticle
Mechanical Characterisation and Modelling of Elastomeric Shockpads
Appl. Sci. 2018, 8(4), 501; https://doi.org/10.3390/app8040501 - 27 Mar 2018
Cited by 1
Abstract
Third generation artificial turf systems are comprised of a range of polymeric and elastomeric materials that exhibit non-linear and strain rate dependent behaviours under the complex loads applied from players and equipment. An elastomeric shockpad is often included beneath the carpet layer to [...] Read more.
Third generation artificial turf systems are comprised of a range of polymeric and elastomeric materials that exhibit non-linear and strain rate dependent behaviours under the complex loads applied from players and equipment. An elastomeric shockpad is often included beneath the carpet layer to aid in the absorption of impact forces. The purpose of this study was to characterise the behaviour of two elastomeric shockpads and find a suitable material model to represent them in finite element simulations. To characterise the behaviour of the shockpads an Advanced Artificial Athlete test device was used to gather stress-strain data from different drop heights (15, 35 and 55 mm). The experimental results from both shockpads showed a hyperelastic material response with viscoelasticity. Microfoam material models were found to describe the material behaviour of the shockpads and were calibrated using the 55 mm drop height experimental data. The material model for each shockpad was verified through finite element simulations of the Advanced Artificial Athlete impact from different drop heights (35 and 15 mm). Finite element model accuracy was assessed through the comparison of a series of key variables including shock absorption, energy restitution, vertical deformation and contact time. Both shockpad models produced results with a mean error of less than 10% compared to experimental data. Full article
(This article belongs to the Special Issue Sports Materials)
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Open AccessArticle
Implications of Rigid Gripping Constraints on Clubhead Dynamics in Steel Golf Shafts
Appl. Sci. 2018, 8(3), 422; https://doi.org/10.3390/app8030422 - 12 Mar 2018
Cited by 1
Abstract
Research and equipment testing with golf robots offers much greater control and manipulation of experimental variables compared to tests using human golfers. However, whilst it is acknowledged that the club gripping mechanism of a robot is dissimilar to that of a human, there [...] Read more.
Research and equipment testing with golf robots offers much greater control and manipulation of experimental variables compared to tests using human golfers. However, whilst it is acknowledged that the club gripping mechanism of a robot is dissimilar to that of a human, there appears to be no scientific findings on the effects of these gripping differences on the clubhead at ball impact. Theoretical and experimental strain propagation rates from the clubhead to the grip and back to the clubhead were determined during robot testing with a 9-iron to determine if this time interval was sufficiently short to permit the gripping mechanism to have an effect on the clubhead during impact. Longitudinal strain appears to propagate the most quickly, but such deflections are likely to be small and therefore of little meaningful consequence. Shaft bending was not a primary concern as modes of large enough amplitude appear to propagate too slowly to be relevant. Torsional strain propagates at a rate which suggests that constraints at the grip end of a golf club could potentially influence impact dynamics for steel shafted irons; however, this effect seems unlikely to be significant, a likelihood that decreases further for longer irons. As such, it is considered reasonable to treat the influence of a robot’s gripping mechanism on clubhead dynamics at impact as negligible, and therefore comparisons between robot and human data in this regard are valid. Full article
(This article belongs to the Special Issue Sports Materials)
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Open AccessArticle
Measurement of Strain and Strain Rate during the Impact of Tennis Ball Cores
Appl. Sci. 2018, 8(3), 371; https://doi.org/10.3390/app8030371 - 04 Mar 2018
Cited by 2
Abstract
The aim of this investigation was to establish the strains and strain rates experienced by tennis ball cores during impact to inform material characterisation testing and finite element modelling. Three-dimensional surface strains and strain rates were measured using two high-speed video cameras and [...] Read more.
The aim of this investigation was to establish the strains and strain rates experienced by tennis ball cores during impact to inform material characterisation testing and finite element modelling. Three-dimensional surface strains and strain rates were measured using two high-speed video cameras and corresponding digital image correlation software (GOM Correlate Professional). The results suggest that material characterisation testing to a maximum strain of 0.4 and a maximum rate of 500 s−1 in tension and to a maximum strain of −0.4 and a maximum rate of −800 s−1 in compression would encapsulate the demands placed on the material during impact and, in turn, define the range of properties required to encapsulate the behavior of the material during impact, enabling testing to be application-specific and strain-rate-dependent properties to be established and incorporated in finite element models. Full article
(This article belongs to the Special Issue Sports Materials)
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Open AccessFeature PaperArticle
Application of Auxetic Foam in Sports Helmets
Appl. Sci. 2018, 8(3), 354; https://doi.org/10.3390/app8030354 - 01 Mar 2018
Cited by 7
Abstract
This investigation explored the viability of using open cell polyurethane auxetic foams to augment the conformable layer in a sports helmet and improve its linear impact acceleration attenuation. Foam types were compared by examining the impact severity on an instrumented anthropomorphic headform within [...] Read more.
This investigation explored the viability of using open cell polyurethane auxetic foams to augment the conformable layer in a sports helmet and improve its linear impact acceleration attenuation. Foam types were compared by examining the impact severity on an instrumented anthropomorphic headform within a helmet consisting of three layers: a rigid shell, a stiff closed cell foam, and an open cell foam as a conformable layer. Auxetic and conventional foams were interchanged to act as the helmet’s conformable component. Attenuation of linear acceleration was examined by dropping the combined helmet and headform on the front and the side. The helmet with auxetic foam reduced peak linear accelerations (p < 0.05) relative to its conventional counterpart at the highest impact energy in both orientations. Gadd Severity Index reduced by 11% for frontal impacts (38.9 J) and 44% for side impacts (24.3 J). The conformable layer within a helmet can influence the overall impact attenuating properties. The helmet fitted with auxetic foam can attenuate impact severity more than when fitted with conventional foam, and warrants further investigation for its potential to reduce the risk of traumatic brain injuries in sport specific impacts. Full article
(This article belongs to the Special Issue Sports Materials)
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Open AccessArticle
Functional Elastic Knits Made of Bamboo Charcoal and Quick-Dry Yarns: Manufacturing Techniques and Property Evaluations
Appl. Sci. 2017, 7(12), 1287; https://doi.org/10.3390/app7121287 - 11 Dec 2017
Cited by 3
Abstract
Conventional sportswear fabrics are functional textiles that can mitigate the impaired muscles caused by exercises for the wearers, but they can also cause discomfort and skin allergy. This study proposes combining two yarns to form functional composite yarns, by using a twisting or [...] Read more.
Conventional sportswear fabrics are functional textiles that can mitigate the impaired muscles caused by exercises for the wearers, but they can also cause discomfort and skin allergy. This study proposes combining two yarns to form functional composite yarns, by using a twisting or wrapping process. Moreover, a different twist number is used in order to adjust the performance of functional composite yarns. A crochet machine is used to make the functional composite yarns into functional elastic knits that are suitable for use in sportswear. The test results show that, in comparison to the non-processed yarns, using the twisted or wrapped yarns can considerably decrease the water vapor transmission rate of functional elastic knits by 38%, while also improving their far infrared emissivity by 13%, water absorption rate by 39%, and air permeability by 136%. In particular, the functional elastic knits that are made of B-wrapped yarns (bamboo charcoal- wrapped yarns), composed of 20 twists per inch, have the optimal diverse functions. Full article
(This article belongs to the Special Issue Sports Materials)
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Review

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Open AccessReview
Review of Auxetic Materials for Sports Applications: Expanding Options in Comfort and Protection
Appl. Sci. 2018, 8(6), 941; https://doi.org/10.3390/app8060941 - 06 Jun 2018
Cited by 23
Abstract
Following high profile, life changing long term mental illnesses and fatalities in sports such as skiing, cricket and American football—sports injuries feature regularly in national and international news. A mismatch between equipment certification tests, user expectations and infield falls and collisions is thought [...] Read more.
Following high profile, life changing long term mental illnesses and fatalities in sports such as skiing, cricket and American football—sports injuries feature regularly in national and international news. A mismatch between equipment certification tests, user expectations and infield falls and collisions is thought to affect risk perception, increasing the prevalence and severity of injuries. Auxetic foams, structures and textiles have been suggested for application to sporting goods, particularly protective equipment, due to their unique form-fitting deformation and curvature, high energy absorption and high indentation resistance. The purpose of this critical review is to communicate how auxetics could be useful to sports equipment (with a focus on injury prevention), and clearly lay out the steps required to realise their expected benefits. Initial overviews of auxetic materials and sporting protective equipment are followed by a description of common auxetic materials and structures, and how to produce them in foams, textiles and Additively Manufactured structures. Beneficial characteristics, limitations and commercial prospects are discussed, leading to a consideration of possible further work required to realise potential uses (such as in personal protective equipment and highly conformable garments). Full article
(This article belongs to the Special Issue Sports Materials)
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