Health monitoring of smart structures by method of wave scattering techniques

Health Monitoring of structures is a topic which is of considerable interest in many fields. Though there are various nondestructive techniques developed over the number of years, most of these techniques are not so sophisticated to suit the requirements of complex structures like aging aircrafts and space structures. The testing techniques available at present cannot detect very small cracks which are buried deep inside the structure but, are critical for structural integrity.;The objective of this research is to introduce a novel technique of health monitoring. Phased arrays of interdigital mesoscale transducers are embedded inside the structure. These transducers play the role of transmitters as well as receivers. An acoustic beam is formed by these transducers and electronically steered throughout the structure. If this beam encounters any damage inside the structure then, that damage acts as a barrier and scatters the signal in all the directions. The amplitude and phase of scattered signal is a function of damage characteristics and hence the scattered signal contains detailed information about the damage.;The research focuses on the analysis of scattered signal for various orientations and crack sizes in two dimension. The scattered signals are analyzed over a number of frequencies and incident angles and at different transducer locations. The relations between the crack parameters (length, orientation and location) and scattered amplitude and power are established.