탄소나노튜브 고분자 복합체는, 외력에 의한 변형에 따라 전기적 저항이 변화하는 피에조저항(piezoresistivity) 거동을 나타낸다. 피에조저항은 고분자 모재 내에서 탄소나노튜브가 형성하는 전기전도망(conductive network)의 변화에 의해서 발현된다. 피에조저항 낮은 탄소나노튜브 함유량에서 더 현저하게 나타난다. 탄소섬유, 카본블랙 등 타 탄소기반 소재에 비해 전기전도도와 길이 대 직경비(aspect ratio)가 월등히 우수하기 때문에, 낮은 탄소나노튜브의 함유량에서도 스트레인 센싱시스템을 구현할 수 있다. 본 연구에서는, 구조물에 부착 또는 임베드 시켜서 구조물의 건전성을 실시간을 진단할 수 있는 탄소나노튜브 고분자 복합체 기반 센싱시스템을 개발하였다. 센서는 열가소성 수지와 다중벽 탄소나노튜브를 사용하여 필름 형태로 제조되었으며, 센싱 성능은 나노복합체를 구조물에 부착한 후 인장, 굽힘, 압축 등의 다양한 형태의 하중을 가하면서 평가하였다.
탄소나노튜브 고분자 복합체는, 외력에 의한 변형에 따라 전기적 저항이 변화하는 피에조저항(piezoresistivity) 거동을 나타낸다. 피에조저항은 고분자 모재 내에서 탄소나노튜브가 형성하는 전기전도망(conductive network)의 변화에 의해서 발현된다. 피에조저항 낮은 탄소나노튜브 함유량에서 더 현저하게 나타난다. 탄소섬유, 카본블랙 등 타 탄소기반 소재에 비해 전기전도도와 길이 대 직경비(aspect ratio)가 월등히 우수하기 때문에, 낮은 탄소나노튜브의 함유량에서도 스트레인 센싱시스템을 구현할 수 있다. 본 연구에서는, 구조물에 부착 또는 임베드 시켜서 구조물의 건전성을 실시간을 진단할 수 있는 탄소나노튜브 고분자 복합체 기반 센싱시스템을 개발하였다. 센서는 열가소성 수지와 다중벽 탄소나노튜브를 사용하여 필름 형태로 제조되었으며, 센싱 성능은 나노복합체를 구조물에 부착한 후 인장, 굽힘, 압축 등의 다양한 형태의 하중을 가하면서 평가하였다.
This paper presents an experimental study on the piezoresistive behavior of nanocomposite strain sensors subjected to various loading modes and their capability to detect structural deformations and damages. The electrically conductive nanocomposites were fabricated in the form of a film using vario...
This paper presents an experimental study on the piezoresistive behavior of nanocomposite strain sensors subjected to various loading modes and their capability to detect structural deformations and damages. The electrically conductive nanocomposites were fabricated in the form of a film using various types of thermoplastic polymers and multi-walled carbon nanotubes (MWNTs) at various loadings. In this study, the nanocomposite strain sensors were bonded to a substrate and subjected to tension, flexure, or compression. In tension and flexure, the resistivity change showed dependence on measurement direction, indicating that the sensors can be used for multi-directional strain sensing. In addition, the sensors exhibited a decreasing behavior in resistivity as the compressive load was applied, suggesting that they can be used for pressure sensing. This study demonstrates that the nanocomposite strain sensors can provide a pathway to affordable, effective, and versatile structural health monitoring.
This paper presents an experimental study on the piezoresistive behavior of nanocomposite strain sensors subjected to various loading modes and their capability to detect structural deformations and damages. The electrically conductive nanocomposites were fabricated in the form of a film using various types of thermoplastic polymers and multi-walled carbon nanotubes (MWNTs) at various loadings. In this study, the nanocomposite strain sensors were bonded to a substrate and subjected to tension, flexure, or compression. In tension and flexure, the resistivity change showed dependence on measurement direction, indicating that the sensors can be used for multi-directional strain sensing. In addition, the sensors exhibited a decreasing behavior in resistivity as the compressive load was applied, suggesting that they can be used for pressure sensing. This study demonstrates that the nanocomposite strain sensors can provide a pathway to affordable, effective, and versatile structural health monitoring.
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문제 정의
This study explores the use of polymer/MWNT films as strain and damage sensing element for structures subjected to various loading modes. In tension and flexure, the resistivity change showed dependence on measurement direction, indicating that the sensors can be used for multi-directional strain sensing.
This study investigates CNT nanocomposites as sensing materialby monitoring electrical resistance of the sensors under various loading modes. The use of electrical resistance has been explored, e.
, for strain and damage sensing in carbon fiber composite structures [20,21] or for damage detection in CNT composite parts [22-26] with promising results. This work focuses on CNT nanocomposite sensors as stand-alone devices that can be affixed, imbedded or otherwise integrated into existing structures. The sensors were fabricated in the form of a film using thermoplastic polymers and multi-walled carbon nanotubes (MWNTs).
대상 데이터
Compressive samples were constructed by sandwiching a circular composite film (5.5 mm in diameter) between two circular copper foils which function as the electrodes (Fig. 2). Two sets of samples were prepared.
5-500 μ m in length, 5-10 nm in ID, and 60-100 nm in OD. The polymers used to fabricate the nanocomposites films include molding-grade PMMA compound (Acrylite S10/8N) from Cyro (Rockaway, NJ) and polycarbonate (Lexan 103) purchased from GE Plastics (Pittsfield, MA).
This work focuses on CNT nanocomposite sensors as stand-alone devices that can be affixed, imbedded or otherwise integrated into existing structures. The sensors were fabricated in the form of a film using thermoplastic polymers and multi-walled carbon nanotubes (MWNTs). The sensing performance was studied by bonding the film-type nanocomposite sensor to a substrate and subjecting it to tension, flexure, or compression.
1. The specimens were constructed from acrylic or Lexan panels for use with PMMA/MWNT or PC/MWNT sensors, respectively. Tensile samples, designated as I and II, and three-point bending samples III and IV measured approximately 140 mm X 20 mm X 2.
이론/모형
A table-top Shimadzu AutoGraph (Kyoto, Japan) micro tensile tester having a 5 kN load cell was used to apply tensile, flexural, or compressive load. Electrical resistance was recorded using a Keithley 2000 (Cleveland, OH) multimeter using two-probe method. For strain and damage sensing samples, resistance was measured between alternating pairs of electrodes, i.
후속연구
Research is in progress to systematically characterize and model the sensing behavior of polymer/CNT nanocomposites and to explore applications beyond conventional strain gages’ capabilities, e.g., strain sensing on irregular surfaces, such as curves or corners, etc.
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