Design of optimal configuration for generating A0 Lamb mode in a composite plate using piezoceramic transducers

Abstract

This work concerned a technique for a health monitoring system based on the generation and sensing of Lamb waves in composite structures by thin surface-bonded piezoceramic transducers. The objective was to develop transducers that are adapted for the damage detection in orthotropic composites. The key problem with the investigated Lamb waves was to select a mode to be sensitive to the damage. A hybrid modeling technique was therefore used to conceive transducers that were adapted to achieve such a feature. This modeling technique enabled studying the influence of the transducer characteristics on the Lamb waves propagating in orthotropic plates. It was demonstrated that a Lamb mode could be generated dominantly to other modes by using a multi-element transducer. The effectiveness of this technique was successfully verified experimentally on composite plates. It was shown that the dominant Lamb mode, obtained by use of dual-element transducers, was an appropriate mode for successfully detecting a damage in composites.

Application of the Piezoelectricity in an Active and Passive Health Monitoring System

“…For the global inspection, stimulations are produced in view to induce a structural response, analysed by the sensors. These stimulations can excite the full structure for modal [7] or static analysis [1], or only a small region for the acousto-ultrasonic technique [8][9].…”

Damage Sensing in Blades

“…The wave modes will be affected by the delamination in different ways depending on its mode of vibration. In the literature (Grondel et al 2002;Su et al 2007;Hu et al 2008;Ramadas et al 2009;Rekatsinas et al 2015), the three fundamental wave modes S 0 , A 0 and SH 0 are the most studied and the most commonly used in order to interrogate a structure. The symmetric mode is chosen at low frequencies, below 200 kHz, because they are less dispersive so the shape of the pulse does not spread along the propagation direction which eases the post-analysis and reduce the complexity of the acquired signals.…”

The effects of the thickness variation on the propagation of Lamb waves in a composite plate

“…최근에는 복합 재의 제조기술 및 주변기술의 발전으로 인하여 램파를 이용한 구조물의 건전성 진단방법에 대한 연구가 많이 진행되고 있다 [2][3][4][5]. 램파는 두께가 얇은 구조물의 내부를 전파하 는 유도 초음파로서 상대적으로 먼 거리를 전파 하기 때문에 경제적이고, 구조물의 내부변화에 민감한 특성을 보이고 있다 [6,7]. 또한 작고 가벼 운 진동자 및 센서를 이용하여 램파의 발생 및 감지가 가능하여 구조물과 일체형으로 설계할 수 있는 장점을 지니고 있다 [8,9] …”