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Lessons from the Lollipop: Biotribology, Tribocorrosion, and Irregular Surfaces

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Biotribology and tribocorrosion are often not included in numerical or computational modeling efforts to predict wear because of the apparent complexity in the geometry, the variability in removal rates, and the challenge associated with mixing time-dependent removal processes such as corrosion with cyclic material removal from wear. The lollipop is an accessible bio-tribocorrosion problem that is well known but underexplored scientifically as a tribocorrosion process. Stress-assisted dissolution was found to be the dominant tribocorrosion process driving material removal in this system. A model of material removal was described and approached by lumping the intrinsically time-dependent process with a mechanically driven process into a single cyclic volumetric material removal rate. This required the collection of self-reported wear data from 58 participants that were used in conjunction with statistical analysis of actual lollipop cross-sectional information. Thousands of repeated numerical simulations of material removal and shape evolution were conducted using a simple Monte Carlo process that varied the input parameters and geometries to match the measured variability. The resulting computations were analyzed to calculate both the average number of licks required to reach the Tootsie Roll® center of a Tootsie Roll® pop, as well as the expected variation thereof.

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The authors thank the students, teachers, and administration of Edgewater High School in Orlando, Florida for their participation. The staff of the Society of Tribologists and Lubrication Engineers generously organized this event, in particular Karl Phipps. The authors would like to acknowledge all of the participants in this study: Ryan M. Nixon, Gilberto Lobaton, Nicholas Calvo, Marina Kay Wiatt, Alexander Rudy, Jessica Rex, Stephen Hugo Arce, Chris Smith, Greg Umali, Mitchell Ochse, Benjamin Rosenblum, Logan Baker, Abraham Watson, Irakli Mikedladze, Kalvin Mitrofan, David Lausberg, Patrick Tran, Joshua Williams, Michael Hataway, Daniel Martinez, Terressa Tong, Tina Ho, Roshani Ekanayake, Victoria Sibons, Devon Guthrie, Emily Mellowe, Jonathan Henderson, William Flowers, Hayes Hartog, Spencer Bennett, Victor Rodriguez, Matthew Rosenthal, Stuart Rodriguez, Addison Radcliff, Max Gonzalez, Kurtis Swearingen, Curtis Mitchell, Conner Enslen, Faith Whittingham, Lanny Wood, Matthew A. Hamilton, Frederik Wolf, Connor Myant, James Batteas, Mckenna Yingling, Brandon Krick, and David L. Burris.

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Correspondence to W. Gregory Sawyer.

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Rowe, K.G., Harris, K.L., Schulze, K.D. et al. Lessons from the Lollipop: Biotribology, Tribocorrosion, and Irregular Surfaces. Tribol Lett 56, 273–280 (2014).

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