Enhanced flexibility and performance from piezocomposite 2D array with a dual-polymer phase improved structure

This paper describes an improved conformable composite array structure, for use in the NDE of irregular surfaces featuring efficient piezocomposite elements as the active array elements and soft polymer phase channels between elements. As each array element is in principle an individual piezocomposite, this device has been named a Composite Element Composite Array Transducer (CECAT). Finite Element (FE) virtual prototyping work identified two possible arrangements for the active phase incorporating either a periodic 1-3 composite or a random piezoceramic fibre structure with examples of both presented. Theoretical simulations and experimental measurements of impedance, surface displacement and mechanical cross talk demonstrate good correlation at an operational frequency of 2 MHz. The CECAT shows superior flexibility and acoustic characteristics over similar piezo-platelet arrangements and comparable sensitivity and bandwidth with a regular 1-3 composite. Enhancement of the piezoelectric performance of each array element is possible through implementation of a dual polymer passive phase configuration.