Effects of ambient conditions on the impedance-based health monitoring technique

In practical application of electro-mechanical impedance (EMI) technique, the monitored structure is constantly undergoing change due to external boundary conditions and the surrounding ambience. This change, in most cases, is considered to be normal and a part of the everyday use of the structure. The aim of this paper is to examine and obtain a better understanding of practical issues that are a result of monitoring the health of structures in an uncontrolled field environment. Comparison study on EMI signatures between the change of ambient conditions and induced structural damages is also implemented. This paper tries to provide an in-depth view through experimental analysis if this health monitoring technique is to be successfully used in practical applications.