다층 압전 필름의 전극 패턴 최적화를 통한 2차원 구조물에서의 모달 변환기 구현

Design of Modal Transducer in 2D Structure Using Multi-Layered PVDF Films Based on Electrode Pattern Optimization

  • 유정규 (국방과학연구소) ;
  • 김지철 (서울대학교 대학원 항공우주공학과) ;
  • 김승조 (서울대학교 공과대학 항공우주공학과)
  • 발행 : 1998.08.01

초록

A method based on finite element discretization is developed for optimizing the polarization profile of PVDF film to create the modal transducer for specific modes. Using this concept, one can design the modal transducer in two-dimensional structure having arbitrary geometry and boundary conditions. As a practical means for implementing this polarization profile without repoling the PVDF film the polarization profile is approximated by optimizing electrode patterns, lamination angles, and poling directions of the multi-layered PVDF transducer. This corresponds to the approximation of a continuous function using discrete values. The electrode pattern of each PVDF layer is optimized by deciding the electrode of each finite element to be used or not. Genetic algorithm, suitable for discrete problems, is used as an optimization scheme. For the optimization of each layers lamination angle, the continuous lamination angle is encoded into discrete value using binary 5 bit string. For the experimental demonstration, a modal sensor for first and second modes of cantilevered composite plate is designed using two layers of PVDF films. The actuator is designed based on the criterion of minimizing the system energy in the control modes under a given initial condition. Experimental results show that the signals from residual modes are successfully reduced using the optimized multi-layered PVDF sensor. Using discrete LQG control law, the modal peaks of first and second modes are reduced in the amount of 12 dB and 4 dB, resepctively.

키워드

참고문헌

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