Three dimensional stress calculation of competitive swimwear using anisotropic hyperelastic model considering stress softening was investigated in this paper. An anisotropic hyperelastic model considering stress softening of swimwear fabrics was introduced in order to reproduce the mechanical characteristics of swimwear fabrics on the analysis. The cyclic tensile loading test was carried out to evaluate the mechanical characteristics of the swimwear fabrics. From the test results, the

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... characteristics of swimwear fabrics show strong-anisotropy and the stiffness of the fabrics shows hardening along with the increase of stretch. Also, the test results show reduction of stiffness which depended on the maximum deformation previously reached in the history of the swimwear fabrics. From the test results, material parameters of the anisotropic hyperelastic model and the stress softening model were approximated. The theoretical calculations were in good agreements with experimental data. In addition, the pressure measurement tests were conducted to measure the pressure of swimwear tightening the cylinder. The theoretical pressure calculated by the proposed model showed similar trend of pressure measurement tests. Finally, 3-dimentional stress calculation of swimwear was conducted using the anisotropic hyperelastic model considering stress softening. The stress calculation enabled the visualization of stress distributions of swimwear. In addition, the torque generated in right and left hip joints were calculated by stress calculation of swimwear. The stress calculation investigated in this study enabled the new design of competitive swimwear considering the torque generated in hip joint.