Abstract Summary
This article presents the fabrication and proof-of-concept evaluation of a new reusable piezo-magnetic composite sensor apt for rapid application of the electro-mechanical impedance (EMI) technique on steel structures with minimal number of sensors. Conventioanlly, the EMI technique employs piezo sensors permanently surface bonded on the structure. However, this not only increases the risk of deterioration over a period, but also demands a large number of piezo sensors to accurately locate damage and assess its severity. The authors have developed several non-bonded sensor configurations, however, all of them involve time consuming installation and dismantling process which warrants high level of expertise. The proposed sensor configuration, on the other hand, deploys a miniaturized hassle-free configuration consisting of a piezo sensor bonded on a detachable magnetic substrate based , imparting it flexibility of multiple usage at various locations of the same structure on a one-by-one basis, thus significantly reducing the number of sensors. It is the capability of most rapid usability from among the reusable sensors developed so far. The earlier configurations warranted very accurate tightening using torque wrench. However, there is no such requirement in the proposed configuration. Repeatability of the proposed sensor has been verified experimentally and found to be excellent in terms of correlation coefficient. The damage sensitivity of the proposed sensor is also found to be of same order as the permanently bonded sensors. In nutshell, the proposed sensor is very much suitable for rapid health assessment of large steel structures in a cost-effective
