Plate Wave Propagation in Transversely Isotropic Materials

In this work, the modes of plate wave propagation in a fiber reinforced com posite (assumed to be transversely isotropic) were investigated. The waves were modeled as harmonic plane waves propagating in the plane of an infinite plate whose bounding sur faces were assumed to be stress free. A numerical analysis procedure was developed to calculate the dispersion relationships for plate waves propagating in arbitrary directions in the plate. Particle displacements and stress distributions were calculated for several im portant propagation modes. Possible applications to nondestructive testing of composites are discussed.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

Piezoelectromechanical structures: new trends towards the multimodal passive vibration control

An intelligent control system has the ability to learn about its environment, process the information to reduce uncertainty, plan, generate and execute actions to either control or reduce to a minimum the undesired motion of all or some of its parts. It generally incorporates sensors, actuators, a controller and a power supply unit. Most of the previous work has focused on active control in which electric power is supplied to the actuators that exert actions on the host structure to suppress its vibrations. Alternatively, undesired mechanical energy of a host structure could be converted into electrical energy that can be dissipated through a set of resistor. This does not require an external power unit and is a more economical means of controlling vibrations of a structure, but an effective transduction of mechanical energy into electric energy has to be guaranteed. Such an effective transduction can be achieved imposing to the electric controller to be resonant at all the mechanical resonance frequencies, and to mimic all the mechanical modal shapes, i.e. to be the analog of the host structure. In this paper we synthesize a completely passive electric circuit analog to an Euler beam, aimed for distributed vibration control

Infrared Thermography

Infrared thermography also commonly referred as thermal imaging, or simply thermography, is a nondestructive testing (NDT) technique that has received vast and growing attention for diagnostics and monitoring in the last few decades. This is mainly due to the fact that commercial infrared or thermal cameras, the main instrument for performing infrared thermography, are continuously improving in both sensibility and in spatial resolution, and they are getting faster and relatively less expensive. Every year or so, it is possible to acquire a better camera for about the same cost as the preceding model from the year before