Wireless Node for Highly Nonlinear Solitary Wave Transducers

A novel nondestructive evaluation (NDE) method based on the application of highly nonlinear solitary waves has recently emerged as a leading candidate for structural health monitoring (SHM) scenarios. The method is based on the actuation and detection of solitary waves propagating along a medium made of uniform spherical particles, the last of which is in contact with the material to be inspected. The typical setup consists of a built-in transducer in dry point contact with the material. The transducer is made of a monoperiodic array of spherical particles in Hertzian contact that enables the excitation and detection of the solitary waves. The transducer is wired to a data acquisition system that controls the functionality of the transducer and store the time series for post-processing. The method relies on the proved hypothesis that the dynamic interaction between the wave and the material/structure in contact with the particle to be inspected is dependent upon the condition of the material/structure. In the study presented in this paper, a wireless node was developed to enable the solitary wave based NDE/SHM without any wired connection to electronic test equipment. Comparative tests and analyses between the measurements obtained with the designed node unit and a conventional wired configuration is provided. Advantages and limitations of the proposed node are given along with some suggestions for future developments.