Date of Award

4-15-2024

Degree Name

Doctor of Philosophy

Department

Mechanical and Aerospace Engineering

First Advisor

Peter Gustafson, Ph.D.

Second Advisor

William Liou, Ph.D.

Third Advisor

Jinseok Kim, Ph.D.

Fourth Advisor

Scott Stapleton, Ph.D.

Keywords

Artificial turf, cleats, computational modeling, football, rotation, studs

Abstract

NFL data exhibits a distinct correlation between an elevated lower extremity injury rate and synthetic surfaces. These ubiquitous injuries frequently relate to excessive foot traction (i.e., failure to release causing fracture or soft tissue damage). Consequently, a discrete element model was developed using open-source software to analyze stud traction. First, laboratory data was collected via bench level experiments covering seventeen different testing scenarios. A minimum of twenty-five samples were collected per scenario. Total work, average torque, and maximum torque were used as indicators of stud grip. And the latter two were statistically analyzed for outliers and significant differences. Next, an infill only model was calibrated against laboratory data to establish the first set of input parameters. This process encompassed multiple design of experiments to assist in developing a correlation between infill input parameters and output torque. Succeeding, a grass+infill model was calibrated and then validated against laboratory data. The validation process involved differing stud counts and designs. Another design of experiments was performed to develop a correlation between input parameters of artificial grass fibers and output torque. Lastly, experiments on the validated model demonstrated reasonable agreement with laboratory data within the quasi-static range but poor agreement in the dynamic range.

Access Setting

Dissertation-Open Access

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