Materials in Sports Equipment

Aleksandar Subic

• Publisher: Woodhead Publishing
• Year: 2019
• ISBN:
  9780081025833
• Edition: 2
• Topic: Technology & Engineering
• Subtopic: Materials Science
• Index: Technology & Engineering

Materials in Sports Equipment, Second Edition, provides a detailed review on the design and performance of materials in sports apparel, equipment and surfaces in a broad range of sporting applications. Chapters cover materials modeling, non-destructive testing, design issues for sports apparel, skull and mouth protection, and new chapters on artificial sport surfaces, anthropometric design customization, and 3D printing in sports equipment. In addition, the book covers sports-specific design and material choices in a range of key sports, from baseball, rowing, and archery, to ice hockey, snowboarding, and fishing.

Users will find a valuable resource that explicitly links materials, engineering and design principles directly to sports applications, thus making it an essential resource to materials scientists, engineers, sports equipment designers and sports manufacturers developing products in this evolving field.

• Provides both updated and new chapters on recent developments in the design and performance of advanced materials in a number of sports applications
• Discusses varying aspects, such as the modeling of materials behavior and non-destructive testing
• Analyzes the aerodynamic properties of materials and the design of sports apparel and smart materials
• Explores new topics on athletic equipment, such as 3D printing and anthropometric design customization and on artificial sports surfaces

Part I

General Issues

Outline

• Chapter 1 Modeling of Materials for Sports Equipment
• Chapter 2 Application of Infrared Thermography in the Assessment of Sport Equipment
• Chapter 3 Protective Helmets in Sports
• Chapter 4 Wearable Technologies in Sportswear
• Chapter 5 Three-Dimensional Printing of Sports Equipment
• Chapter 6 Mouth Protection in Sports

Chapter 1

Modeling of Materials for Sports Equipment

Martin Strangwood, The University of Birmingham, Birmingham, United Kingdom

Abstract

The chapters in Part II of this book cover the design and materials used in particular sports with an emphasis on how the interrelationship of design and materials affects performance. In the field of sports equipment—as in all other applications such as aerospace, automotive, and biomedical—it is the combination of materials and design that achieves the requirements specific to that application. The most suitable materials for the application are, therefore, those that most completely and readily achieve the mix of properties (mechanical, physical, chemical, and nontechnical) in the desired shapes and dimensions. In this way “sports materials” do not differ from any other type of “material,” but are materials designed for the operating conditions pertinent to sporting applications. Of the particular sports covered in Part II, the operating conditions are between −5°C and +40°C, involve exposure to moisture, and cover a range of strain rates. Additionally, sports equipment, such as bats and clubs, interact strongly with the athletes using them. This includes force transfer and vibrations to the athletes, whose soft tissue can suffer damage and injury at strains and strain rates that would be negligible for structures such as aircraft or power generation plants.

Keywords

Metallic alloy; polymers; composites; laminates; Euler buckling; alloy strength

1.1 Introduction

The chapters in Part II of this book cover the design and materials used in particular sports with an emphasis on how the interrelationship of design and materials affects performance. In the field of sports equipment—as in all other applications such as aerospace, automotive, and biomedical—it is the combination of materials and design that achieves the requirements specific to that application. The most suitable materials for the application are, therefore, those that most completely and readily achieve the mix of properties (mechanical, physical, chemical, and nontechnical) in the desired shapes and dimensions. In this way “sports materials” do not differ from any other type of “material,” but are materials designed for the operating conditions pertinent to sporting applications. Of the particular sports covered in Part II, the operating conditions are between −5°C and +40°C, involve exposure to moisture, and cover a range of strain rates. Additionally, sports equipment, such as bats and clubs, interact strongly with the athletes using them. This includes force transfer and vibrations to the athletes, whose soft tissue can suffer damage and injury at strains and strain rates that would be negligible for structures such as aircraft or power generation plant.

Modeling of materials covers a range of scales and outcomes that relate to different engineering disciplines, including:

1. 1. Atomistic or ab initio modeling (Wahn & Neugebauer, 2006) based on interatomic potentials which can be used to design specific localized properties, such as doping of semiconductor devices.
2. 2. Analytical models: these operate at the micron to millimeter scale and involve thermodynamics and kinetics for structural changes as well as dislocation motion relating to strength and fracture. They are used in designing material compositions and microstructures to achieve properties over a limited portion of the structure (Ghosh, Van de Walke, Asta, & Olson, 2002; Robson, 2004). This could be viewed as the ideal or target composition and microstructure for the processed component.
3. 3. Process modeling (Grong, 1994): these models often involve numerical methods, such as finite element (FE) and computational fluid dynamics in order to determine thermomechanical and fluid flow conditions throughout complete components such as shaped castings or forgings. They give structures and properties which are more average, that is, they do not have the fine-scale resolution of structure possible in (2), but do give variations across full components and can predict defects such as porosity in castings (Lee, Chirazi, Atwood, & Wang, 2004).
4. 4. Continuum mechanics: these models (also often numerical) are used to define the properties, for example, strength and stiffness, required at different positions throughout the component.

Design and materials for various applications are assisted through computational modeling based mostly on an iterative combination of (2)–(4), although the resources of smaller manufacturers may only allow some aspects, for example (4), to be carried out. Models are only as good as the data that they use and, therefore, if a full mix of models and data are not available, it is important to understand which of the many database values usually available are appropriate for use in the models. As the range of properties and materials is very wide, this chapter will concentrate on the more commonly used materials (metallic alloys, polymers, and polymer matrix composites) and properties (modulus and yield stress) encountered in sporting applications.

1.2 Properties of Metallic Alloys

Table 1.1 summarizes the range of mechanical properties of metallic systems commonly encountered in golf equipment and is typical of the data available in materials handbooks (e.g., Boyer, Welsch, & Collings, 1994) or online sources such as www.matweb.com. In general, the density values of the alloys do not vary much, usually because the amounts of alloying elements present are limited. An exception is when the atoms are similar in size (and hence mass) as for Fe and Cr in stainless steels. Titanium-based systems are also an exception due to the greater solubility of elements in titanium, with the three alloys in Table 1.1 showing a 10% variation in density. Of the other alloy systems, only the addition of Li to Al results in a decrease in density (up to 7% reduction), which also increases the Young’s modulus (by up to 10%). The beneficial improvements in density and modulus are accompanied by strength increases, but at the expense of reduced formability, toughness, and easier crack formation.

Table 1.1

Summary of typical metallic alloy properties

Alloy	Density, ρ (g/cm^3)	Young’s modulus, E (GPa)	Yield stress, σy (MPa)	Tensile strength, UTS (MPa)	Ductility (%)
C–Mn (mild) steel	7.85	210	210–350	400–500	15–35
High-strength steel, e.g., 4340	7.85	207	860–1620	1280–1760	12
316 stainless steel	7.85	195	205–310	515–620	30–40
Cu–Be	8.25	128	200–1200	450–1300	4–60
Al–Cu	2.77	73	75–345	185–485	18–20
Al–Mg	2.77	70	130–192	225–275	7–22
Mg–Ti	1.78	45	200–220	260–290	15
Ti–3Al–2.5V	4.50	105–110	750	790	16
Ti–6Al–4V	4.43	110–125	830–1100	900–1170	10–14
Ti–15V–3Al–3Si–3Cr (β-titanium)	4.71	85–120	800–1270	810–1380	7–16

Stiffness for efficient energy transfer...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• List of Contributors
• Part I: General Issues
• Part II: Specific Sports
• Index