In this study, the finite element analysis of the string planes of badminton racquets was investigated to evaluate the effect of the mechanical characteristics of polymer strings. The nonlinear mechanical characteristics of commercially available polymer strings were obtained by the uniaxial loading tests experimentally. The effects of the strain rate on the mechanical characteristics of the polymer strings were also investigated to consider the dynamic effect on the numerical simulation. The numerical simulation code used to analyze the string planes of the badminton racquets was developed originally. A nonlinear elastic model (Yeoh model) was applied to the mechanical characteristics of the polymer string. Simulated results were compared with the experimental results. The effect of the mechanical characteristics of the polymer strings and the geometrical shape of the badminton racquets on the out-of-plane stiffnesses were investigated.

The effect of string pattern on the mechanical characteristics of a tennis racket were simulated numerically. A numerical simulation program to evaluate deformation of the string bed of a tennis racket was developed using the finite element method. The formulation of a numerical simulation code is described in this paper. The applicability of the developed simulation program was investigated by comparing experimental results of loading tests on string bed specimens, for which the distance between strings was 12 mm. The out-of-plane stiffness and sliding characteristics of strings of an actual racket were simulated using the developed simulation code.