Shape optimization for low pressure and low speed hyperelastic seal using genetic algorithm

Abstract

In this study, the cross-sectional shape of a seal was optimized by using the genetic algorithm to develop a hyperelastic seal that can be used in low-pressure and low-speed environments. Conventional seals are mainly used under high-pressure and high-speed conditions. However, since medical devices such as aspirators and techniques such as negative pressure wound therapy (NPWT) are employed under low-pressure and low-speed conditions, there is a demand for seals that can be used in such environments. Because hyperelastic seals exhibit nonlinear and incompressible behavior, we performed simulations based on a fluid-structure interaction analysis, in which data are directly transferred between the fluid and the structure. In the optimization method, minimization of the frictional force is regarded as an objective function, and the constraint is set such that the contact pressure is equal to or greater than the fluid pressure. Two types of silicon materials were used for comparison, and uniaxial and biaxial tensile tests were performed to obtain the material properties of the hyperelastic material. Experiments were performed to measure the frictional force, and the proposed seals was validated by comparing the experimental values and simulation values. The seals optimized using the genetic algorithm showed less variation in the frictional force. In addition, Dragon SkinTM 20, which has relatively less frictional force than Mold StarTM 30—the other material studied, has good sealing efficiency and excellent abrasion resistance, and hence, a long life can be expected.