Excitation of dominant flexural guided waves in elastic hollow cylinders using time delay circular array transducers

•The NME is adopted to analyze the excitation of dominant flexural waves in pipes.•A time delay circular array transducer is proposed to excite dominant flexural mode.•Expression to calculate time delay for exciting a specific flexural mode is given.•Numerical evaluations indicate that dominant flexural waves are efficiently excited.

A time delay circular array transducer (TDCAT) is proposed to selectively excite a dominant flexural guided wave mode in an elastic hollow cylinder. The classical Normal Mode Expansion method (NME) is adopted to disseminate the forced response and perturbation analysis of a hollow cylinder with respect to a time delay circular array loading. A single dominant flexural mode is effectively excited in a hollow cylinder by a TDCAT with appropriate time delay parameters. The expression for calculation of time delay parameters to excite a specific flexural mode is given. Numerical evaluations that demonstrate the generation of dominant flexural modes in elastic hollow cylinders are carried out for both torsional and longitudinal flexural modes. A TDCAT with eight elements is recommended for practical flexural guided wave utilizations after studying the influence of element number on flexural wave excitation.