This paper studied a new shape unit model based on Gibson and Ashby's theory. As a result of theoretical research, the relative density equation is correlated with relative elasticity, and through this study, the theoretical relationship between the relative elasticity equation was defined. The relative elasticity equation was defined based on the model for which the analysis was performed. According to the analysis results, the diameter of the model was set to 3 mm, and the maximum stress values were confirmed by reflecting the same boundary conditions. The maximum stress for each model is 5668.9MPa for Type 1, 5136.7MPa for Type 2, 5642MPa for Type 3, and 6032.9MPa for Type 4 when the truss diameter is 3mm. The relative elasticity equation was defined based on this condition. In the future, compression analysis will have to be performed in the same way, reflecting the diameter of the truss at 5 mm and 7 mm, to find and define the coefficients of the relative elasticity equation, and verification through experiments will have to be carried out based on the theoretical equation. In addition, in order to be applied in each field, proof through prototype production and installation must be carried out.

본 논문에서는 인장 좌굴 현상을 소개하고 이를 이용한 음의 포아송 효과를 가지는 구조물에 대한 분석을 다룬다. 일반적으로 널리 알려진 좌굴은 압축하중 하에서의 안정성 문제임에 반하여, 인장 좌굴은 인장에 의해 국소적으로 압축력이 생겨 발생하는 좌굴이다. 고전적인 좌굴에 비하여 비교적 최근의 연구이기 때문에 상대적으로 잘 알려지지 않았다. 이에 인장 좌굴 현상을 에너지 관점에서 고 찰하고, 해석을 위하여 비틀림 스프링을 가지는 비선형 트러스 유한요소의 정식화를 수행하였다. 비선형해석을 통해 후좌굴 거동을 분석하고 비틀림 스프링이 주요 인자임을 확인하였다. 이러한 후좌굴 거동은 음의 포아송 비를 가지는 구조물에 적용할 수 있으며, 기 계적 스위치 등의 장치에 적용할 가능성을 보였다. 얻어진 결과들의 정확성 확인을 위하여 해석해와 상용 유한요소해석 결과들과 비 교하여, 개발된 유한요소 모델이 기초 설계에 유용함을 보였다.

In this paper, the dynamic snapping of the 3-free-nodes spatial truss model was studied. A governing equation was derived considering geometric nonlinearity, and a model with various conditions was analyzed using the fourth order Runge-Kutta method. The dynamic buckling phenomenon was observed in consideration of sensitive changes to the force mode and the initial condition. In addition, the critical load level was analyzed. According to the results of the study, the level of critical buckling load elevated when the shape parameter was high. Parallelly, the same result was caused by the damping term. The sensitive asymmetrical changes showed complex orbits in the phase space, and the critical load level was also becoming lowly. In addition, as the value of damping constant was high, the level of critical load also increases. In particular, the larger the damping constant, the faster it converges to the equilibrium point, and the occurrence of snapping was suppressed.