3D Auxetic Pyramid 구조의 최적화 연구 "Auxetic is a structure that behave as negative Poisson’s ratio. It is known for high mechanical property like energy absorption and destruction toughness so far. In this paper, we aimed to design auxetic structure which has small internal energy when force is applied and high NPR and over 50N/mm stiffness by using optimization method. We defined length(L), thickness(t), angle(theta theta 1, theta theta 2) as design factors and also von-Mises stress, NPR, stiffness as reaction factors. We used Box-Behnken method and conducted 4factors - 3levels experiment design. We also analyzed each models by using CSD_EPLAST, Edison program, and did extra analysis for more accurate results. Finally, we found out the optimal design factors which is satisfied aimed value and increased reliability through factor analysis and validity verification."