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Effect of Changing Table Tennis Ball Material from Celluloid to Plastic on the Post-Collision Ball Trajectory

View Article: PubMed Central - PubMed

ABSTRACT

The official material used in table tennis balls was changed from celluloid to plastic, a material free of celluloid, in 2014. The purpose of this study was to understand the differences and similarities in the two types of ball materials by comparing their behavior upon collision with a table. The behavior of the balls before and after collision with a table, at various initial speeds ranging from 15 to 115 km/h, was captured using high-speed cameras. Velocities and spin rates before collision and velocities after collision were computed to calculate the coefficients of restitution and friction. Based on the computed variables, the post-collision trajectories of both balls were calculated by integrating the equation of motion of the ball for simulated service, smash and drive conditions with respect to time. The coefficients of restitution were higher for the plastic balls than the celluloid ones when the initial vertical velocities were higher. The coefficients of friction were higher for plastic balls when the initial horizontal contact point velocities were slower. Because of the differences in the material characteristics, the plastic ball trajectories of services with backspin and drives with great topspin were expected to be different from those of celluloid balls. Since the extent of differences between the two ball types varied depending on the initial conditions, testing at various initial conditions was suggested for comparing and understanding the characteristics of the balls.

No MeSH data available.


Related in: MedlinePlus

Estimated trajectory of the balls after collision with the table at (a) service conditions, (b) smash condition, and (c) (d) drive conditions at medium and high top-spin.
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j_hukin-2017-0004_fig_003: Estimated trajectory of the balls after collision with the table at (a) service conditions, (b) smash condition, and (c) (d) drive conditions at medium and high top-spin.

Mentions: The post-collision trajectories of balls of a different type having the same initial conditions were compared. To simulate a service, the initial conditions were set as follows: vh_before= 21.0 km/h, vz_before= −8.0 km/h, and spin rate = 60 rps (backspin) according to Yoshida (2014). The computed conditions of the ball after collision for celluloid and plastic balls were as follows: vh_after= 17.2 km/h, vz_after= 7.7 km/h, and spin rate = 47 rps (backspin) for the celluloid ball, and vh_after= 16.3 km/h, vz_after= 7.7 km/h, and spin rate = 44 rps (backspin) for the plastic ball. Because of the greater deceleration in plastic balls during collision, the simulated trajectories for 0.5 s were different between ball types (Figure 3a). At 0.5 s, the plastic ball was located 9.3 cm behind and 1.9 cm below the position of the celluloid ball at the same instant.


Effect of Changing Table Tennis Ball Material from Celluloid to Plastic on the Post-Collision Ball Trajectory
Estimated trajectory of the balls after collision with the table at (a) service conditions, (b) smash condition, and (c) (d) drive conditions at medium and high top-spin.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC5304273&req=5

j_hukin-2017-0004_fig_003: Estimated trajectory of the balls after collision with the table at (a) service conditions, (b) smash condition, and (c) (d) drive conditions at medium and high top-spin.
Mentions: The post-collision trajectories of balls of a different type having the same initial conditions were compared. To simulate a service, the initial conditions were set as follows: vh_before= 21.0 km/h, vz_before= −8.0 km/h, and spin rate = 60 rps (backspin) according to Yoshida (2014). The computed conditions of the ball after collision for celluloid and plastic balls were as follows: vh_after= 17.2 km/h, vz_after= 7.7 km/h, and spin rate = 47 rps (backspin) for the celluloid ball, and vh_after= 16.3 km/h, vz_after= 7.7 km/h, and spin rate = 44 rps (backspin) for the plastic ball. Because of the greater deceleration in plastic balls during collision, the simulated trajectories for 0.5 s were different between ball types (Figure 3a). At 0.5 s, the plastic ball was located 9.3 cm behind and 1.9 cm below the position of the celluloid ball at the same instant.

View Article: PubMed Central - PubMed

ABSTRACT

The official material used in table tennis balls was changed from celluloid to plastic, a material free of celluloid, in 2014. The purpose of this study was to understand the differences and similarities in the two types of ball materials by comparing their behavior upon collision with a table. The behavior of the balls before and after collision with a table, at various initial speeds ranging from 15 to 115 km/h, was captured using high-speed cameras. Velocities and spin rates before collision and velocities after collision were computed to calculate the coefficients of restitution and friction. Based on the computed variables, the post-collision trajectories of both balls were calculated by integrating the equation of motion of the ball for simulated service, smash and drive conditions with respect to time. The coefficients of restitution were higher for the plastic balls than the celluloid ones when the initial vertical velocities were higher. The coefficients of friction were higher for plastic balls when the initial horizontal contact point velocities were slower. Because of the differences in the material characteristics, the plastic ball trajectories of services with backspin and drives with great topspin were expected to be different from those of celluloid balls. Since the extent of differences between the two ball types varied depending on the initial conditions, testing at various initial conditions was suggested for comparing and understanding the characteristics of the balls.

No MeSH data available.


Related in: MedlinePlus