The HINDSYHT project aims to develop and test a complete, versatile and unobtrusive structural health monitoring system based on ultrasonic non-destructive testing methods. The proposed system will enable the end-user to assess the mechanical characteristics of the structure under test with the means otherwise only available in a laboratory setting or via advanced data acquisition systems, orders of magnitude larger both in terms of cost and size. This will be made possible with the use of state-of-the art technology in an innovative and integrated manner that will enable the satisfaction of the project’s technological objectives.

The NDT method to be used is that of ultrasonic testing in which piezoelectric transducers of appropriate resonant frequency are acoustically coupled to the structure under test and are used to ensonify parts of the structure with ultrasonic waves. These acoustic waves propagate through the material while experiencing changes in their characteristics as they are being sensed by a second piezoelectric transducer. These changes are attributed to physical phenomena such as the absorption factor, dispersion, reflection/transmission coefficient, mode conversion, etc., and correlate well with the material’s mechanical status. By sensing these changes and comparing them to previous records or with expected acoustic signatures it is envisaged that a structure’s performance can be evaluated. Deterioration such as cracks, delamination, welding imperfections or weakening can be quantified and localised. Ultrasonic testing benefits from ease of installation to the structure using standardised methods and coupling materials. The ultrasonic emissions exhibit high degrees of background low-frequency noise immunity, great depth of penetration and also pose no health risks to the bystanders. It is also possible to have relatively low-cost sensing/emitting piezoelectric elements manufactured to high standards able to withstand harsh environments.