DOI QR코드

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극대화된 밴드갭을 갖는 켈빈 격자 구조의 아이소-지오메트릭 최적 설계

Isogeometric Optimal Design of Kelvin Lattice Structures for Extremal Band Gaps

  • 최명진 (서울대학교 조선해양공학과) ;
  • 오명훈 (서울대학교 조선해양공학과) ;
  • 조선호 (서울대학교 조선해양공학과) ;
  • 구본용 (군산대학교 기계융합시스템공학부)
  • Choi, Myung-Jin (Department of Naval Architecture and Ocean Engineering, Seoul National University) ;
  • Oh, Myung-Hoon (Department of Naval Architecture and Ocean Engineering, Seoul National University) ;
  • Cho, Seonho (Department of Naval Architecture and Ocean Engineering, Seoul National University) ;
  • Koo, Bonyong (School of Mechanical Convergence System Engineering, Kunsan National University)
  • 투고 : 2019.06.22
  • 심사 : 2019.07.09
  • 발행 : 2019.08.31

초록

밴드갭은 기계적 파동의 전파가 금지되는 특정 주파수 범위를 의미한다. 본 연구는 경사도 기반의 설계 최적화 방법을 사용하여 낮은 가청 주파수 범위에서 밴드갭을 갖는 3차원 켈빈 격자를 설계하는 것을 목적으로 하고 있다. 블로흐 이론을 이용하여 무한주기 격자에서의 탄성파 전파를 해석하고, 기하학적으로 엄밀한 빔 이론에서 선형화를 통해 얻은 전단 변형 가능한 빔 모델을 사용하여 격자 구조 연결선을 모델링하였다. 주어진 격자 구성에서 중립 축 및 단면 두께를 B-spline 함수를 이용한 아이소-지오메트릭 매개화를 통해 설계 변수로 정의하고, 격자 구조의 밴드갭의 크기를 극대화하는 최적 설계를 수행하였다.

A band gap refers to a certain frequency range where the propagation of mechanical waves is prohibited. This work focuses on engineering three-dimensional Kelvin lattices having external band gaps at low audible frequency ranges using a gradient-based design optimization method. Elastic wave propagation in an infinite periodic lattice is investigated by employing the Bloch theorem. We model the ligaments using a shear-deformable beam model obtained by consistent linearization in a geometrically exact beam theory. For a given lattice topology, we enlarge band gap sizes by controlling the configuration of the beam neutral axis and cross-section thickness that are smoothly parameterized by B-spline basis functions within the isogeometric analysis framework.

키워드

참고문헌

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