Author(s) :

Ian Seungbin Shin.

Volume/Issue :

Abstract :

Traditional sports balls use an internal pressurized rubber core for bounce but suffer from pressure loss and limited lifespan. Airless sports balls replace this core with a rubber or plastic lattice structure, mitigating these issues. This study examines material properties influencing the rebound performance of airless tennis balls, using seventeen 3D printing filaments in a standardized design compared against a regulation pressurized ball. Mechanical properties (Young’s modulus, tensile strength, elongation at break, and impact strength) were sourced from manufacturer datasheets, while damping behavior was measured via free-vibration decay of printed cantilever beams. Each filament had one cantilever beam with three filmed trials, averaged for analysis. Rebound performance was evaluated through coefficient of restitution (COR) and rebound reliability (success rate) across repeated drop tests, which were continued until three vertical rebounds were achieved. Results show damping time as the strongest predictor of COR, with longer damping times yielding higher values. Rebound reliability correlated negatively with Young’s modulus and tensile strength, suggesting that moderate stiffness and strength favor consistent vertical rebounds. Impact strength was linked to durability, with low values correlating with fracture under repeated impact. A performance map plotting COR against rebound reliability identified optimal filament candidates for replicating pressurized ball performance, excluding fragile f ilaments. Materials with moderate stiffness, low damping, and high impact strength demonstrated the best balance of rebound magnitude, consistency, and durability. Future work should investigate filament blending to optimize stiffness and damping, lattice geometry effects, and long-term durability.