Materials in Sport: Materials in Sport
Sponsored by: TMS Structural Materials Division, TMS: Composite Materials Committee
Program Organizers: Brian Love, University of Michigan; W. Jud Ready, Georgia Institute of Technology; Nikhilesh Chawla, Purdue University

Monday 8:30 AM
February 28, 2022
Room: 251C
Location: Anaheim Convention Center

Session Chair: Nikhilesh Chawla, Purdue University; W. Jud Ready, Georgia Institute of Technology; Brian Love, University of Michigan

8:30 AM Introductory Comments

8:35 AM  
Material Characterization of Nordic Ski Waxes: Jeffrey Bates1; 1University of Utah
    The ski industry has developed kicking and gliding waxes for use in Nordic skiing; however, the material performance is not well understood, and the methods for testing glide performance are far from standardized. The ski industry has hypothesized that the coefficient of friction and the hydrophobicity of the ski wax material are the leading contributors to glide performance. However, the properties of short-chain and low molecular weight polymer materials are highly dependent upon temperature and interfacial conditions. In this work, we present the material properties of Nordic ski waxes as a function of temperature and moisture content at the ski wax surface, specifically the coefficient of friction, the contact angle, the thermal properties, and other parameters that may play a role in the performance of ski wax materials.

8:55 AM  
"Stuck on You": Functional Friction Measurements of Doctored Baseballs Coated with "Sticky Substances": Brian Love1; 1University of Michigan
    We've entered into an absurd new era of ball management and extremes found in professional baseball. Ball contact seems to be at an all-time low, and spin rates of balls being thrown by pitchers have been at all-time high. Perhaps these are effects and cause. These extremes are attributed to substances that are dispensed on/near players fingers and gloves including bug sprays, sunscreens, rosins and tars, and other OTC adhesives like Spider tack and Stickum. In quantifying the stickiness of doctored balls, we are doing some backyard experiments with coated leather baseballs using a controllable, angle dependent, rolling force measurement tool adapted to track rolling length after rolling downhill a certain distance. We will present details of the functional test, comparisons between doctored and virgin balls, both at room temperature and after being equilibrated at 5oC to mimic cold game conditions.

9:15 AM  
Additive Manufacturing for Adjustable Putters: Brittan Pero1; Caroline Means1; Jaime Berez1; Elliott Jost1; Jason Kuiper2; Justin Martin2; Stewart Cink3; Chris Saldana1; 1Georgia Institute of Technology; 2Bobby Jones Golf Course; 3PGA Tour
    The advent of metallic additive manufacturing has resulted in new possibilities in the world of sports equipment with the ability to create a highly customizable golf putter. With our novel design, golfers can pick the face material and the loft of the club by selecting 3D-printed face inserts in order to account for course conditions. The openness of their club is determined by the redesigned point of attachment between the shaft and club head, so players have the ability to make minute adjustments as their swing changes. In short, a single club can achieve multiple configurations. Using high-end ball tracking technology, the relationship between ball control, loft, and face material is exploited to improve design. From unique lattice structures to metallic gradients in a singular cohesive club head, we are in pursuit of the perfect putter for each player.

9:35 AM  
Viscoelastic Self-sensing Nano-composite Materials and Their Use in Sports Applications: David Fullwood1; Isaac Sorensen1; Jacob Carter1; Kurt Jensen1; Ryan Hanson1; Spencer Baker1; Adam Bilodeau1; Matthew Seeley1; Ulrike Mitchell1; Anton Bowden1; 1Brigham Young University
    Recent developments in wearable technology represent an accelerating area of scientific development for sports applications. In particular, materials technologies that incorporate sensing capabilities and are compatible with typical human levels of biomechanical deformation are an exciting and emerging field of exploration. This paper reports on piezoresponsive nano-composite foam and films that can be incorporated into sportswear for monitoring biomechanical activity. Specific recent focus by the authors includes knee sleeves and footwear insoles for tracking lower-extremity biomechanics during some human movements that are common to sport. In particular, the viscoelastic response of the base polymeric material is studied in order to deliver more accurate dynamic interpretation of the data gathered from the sensing components – an issue not typically associated with traditional sensing devices. Numerous sportswear applications stand to benefit from understanding the underlying material science of the polymeric nano-composite materials, including the ability to monitor helmets, padding, footwear, clothing, etc.

9:55 AM Break

10:15 AM  
Materials Science and Engineering of Multiscale Foams for High Performance Footware: Arun Sundar Singaravelu1; Max Drexler2; Jasmine Rupert2; Chris Holmes2; Eshan Ganju3; Nikhilesh Chawla3; 1Arizona State University; 2adidas; 3Purdue University
    Energy return in footwear is connected to damping behavior of midsole foams, which stems from the combination of cellular structure and polymeric material behavior. Traditional EVA foams, for example, have been replaced by BOOSTTM foams, which have a multi-scale structure, consisting of porous beads at meso-scale and thousands of small closed cells within beads at micro-scale. In this talk, I will describe experiments and simulations that address the critical link between foam structure and compression behavior of multiscale, high performance foams, by using a three-dimensional (3D) virtual microstructure obtained by lab-scale and x-ray synchrotron tomography. The approach involves capturing the microstructure by novel and sophisticated in situ testing in an x-ray synchrotron, followed by x-ray tomography and image analysis, and 3D reconstruction of the microstructure. The effect of the functionally graded foam microstructure and the effect of strain rate on the damage evolution were studied and will be discussed.

10:35 AM  
Measuring Cool Touch of Key Sports Performance Apparel T-shirt Materials Using a Modified Transient Plane Source (MTPS) Sensor to Inform Future Technology Development: Susan Sokolowski1; Emily Karolidis1; Arya Hakimian2; 1University of Oregon; 2CTherm
    The sports performance apparel industry leads the effort of innovating textiles to keep athletes cool while training and competing. Recently there is a trend where sports product manufacturers desire to develop textiles that have a cool touch. Cool touch textiles can provide an athlete next-to-skin comfort but can also influence point-of-purchase decisions and be used as a marketing tool – as the consumer can feel for themselves the cool-touch benefit when shopping. This presentation will overview a method of measuring cool touch for eight common sport T-shirt materials, using a Modified Transient Plane Source (MTPS) sensor. The method will be compared to QMax and results will demonstrate opportunities for future materials development. When cool touch is coupled with other sport textile performance characteristics (e.g., anti-cling, moisture transfer, air-permeability) manufacturers can create their own intellectual property and have a competitive point-of-difference in the market.

10:55 AM  
A Mechanical Behavior Comparison between Cloth and Elastomeric Kinesiotapes Used in Athletic Training and Rehabilitation: Declan Shannon1; Brian Love1; 1University of Michigan
    Quasi-static tensile and stress relaxation experiments were performed on several cloth-based and segmented elastomeric tapes and the results were analyzed using viscoelastic models. The cloth tape modulus of elasticity was ~ 340 MPa, while those of the kinesio tapes ranged from ~ 15-20 MPa. The cloth tapes were also stronger and more brittle. Viscoelastic modeling of the stress relaxation behavior was done using a Zener model for the cloth tapes and a 5-element model for the kinesio tapes. The cloth tapes relaxed by ~ 20%, while the kinesio tapes relaxed up to ~ 50% of the applied maximum stress during the 300 second duration of our constant strain experiments. The overall amount of long-term compressive force delivered by kinesio tapes might be inadequate for some uses, but the tapes are more forgiving in how they are deployed.

11:15 AM  
Adding a New Dimension to Activewear Fabrics: One-Way Transport Leveraging Biomimicry Science instead of Chemical Treatments for Perspiration Transport: Chad Lawrence1; Jordan Lightstone1; Jason Hu1; 1NexTex Innovations, Inc.
    TurboDryŽ is an innovative fabric technology that utilizes biomimicry to keep active users dryer and more comfortable than regular wicking materials. A patented knitting process and yarn material selection optimize contact angles that transports moisture away from the wearer’s body. Capillaries knit into the fabric move the moisture to the fabric exterior where it spreads and rapidly evaporates. TurboDry technology is designed to mimic the capillary action that plants use to move water from their roots to their leaves. It does not rely on chemical coatings, reducing its impact on the environment. Additionally, it can be made in mono-component constructions, allowing for easy recycling at the end of the garment's life.

11:35 AM Concluding Comments