3D-CG Based Stress Calculation of Competitive Swimwear Using Anisotropic Hyperelastic Model

Abstract

A new design method for designing competitive swimsuits using 3-dimensional stress calculation was investigated in this paper. An anisotropic hyperelastic modeling of swimwear fabric was developed from the results of tensile loading tests. 3-dimensional stress distributions of swimwear in swimming motions were calculated by the anisotropic hyperelastic model. The displacement fields of 3D-CG human model which reproduce swimming motion of human body were applied to stress calculation. For the material modeling, the uniaxial cyclic tensile loading tests were conducted to obtain the mechanical characteristics of competitive swimsuits. From loading test results, the mechanical characteristics of swimwear fabrics show strong-anisotropy and the stiffness of the fabric shows hardening along with the increase of stretch. The cyclic tensile loading test results shows reduction of stiffness which depended on the maximum deformation previously reached in the history of the material. To take the strong anisotropy and stress reduction into account for the material modeling, a stress-softening model for anisotropic hyperelastic model using stiffness ratio of warp or weft was proposed. The results of the simulation showed good agreement with that of pressure test in a design range of competitive swimsuits. Finally, 3-dimensional stress distributions of swimwear were calculated by the proposed anisotropic hyperelastic model. A polygonal model of the swimwear was prepared and deformation of swimwear was adapted to the skin of 3D-CG human model in swimming motions. From the results, stress distributions were able to be visualized on the 3D-CG swimwear model.