Optimization design and experimental study for flexible fan-shaped interdigital guided wave transducer

To address the challenges of difficult attachment to a rigid substrate and large-area damage scanning on planar and curved panel structures, a novel flexible fan-shaped interdigital guided wave transducer (FFIGWT) is proposed. It consists of a fan-shaped interdigital electrode and a Polyvinylidene Fluoride (PVDF) flexible smart material substrate. The positive interdigital electrode is divided into inner and outer parts, enabling the FFIGWT to simultaneously excite and receive guided waves. Numerical simulations are conducted to investigate the influence of PVDF substrate thickness on wave excitation and reception, as well as the effect of the ratio between the inner and outer radius of the FFIGWT on excitation intensity. The results demonstrate that the reception and excitation of guided waves by the FFIGWT improve with increasing PVDF substrate thickness. The ratio between the inner and outer radius of the transducer's interdigital electrode is positively correlated with excitation intensity. Additionally, the transducer's beam divergence angle approaches the designed angle span of the FFIGWT with an increasing ratio between the inner and outer radius. Experimental validation confirms that the FFIGWT exhibits significantly enhanced wave excitation and reception capabilities in the corresponding FFIGWT region, making it suitable for composite material detection applications. [Display omitted] •Design the shape of the interdigital electrode including two inner and outer electrodes.•Simulations are conducted to investigate the influence of PVDF substrate thickness on wave excitation and reception.•An experimental calibration platform specific to the transducer was set up and measure the excitation and reception performance.