1. Introduction The development of a real-time, in-service structural health monitoring and damage detection technique has recently attracted a large number of academic and industrial researchers. The goal of this research is to allow systems and structures to monitor their own integrity while in operation and throughout their lives in order to prevent catastrophic failures and to reduce the co...

The electromechanical (E/M) impedance method is a powerful technique in active structural health monitoring (SHM). E/M impedance method utilizes as its main apparatus an impedance analyzer that reads the in-situ E/M impedance of piezoelectric wafer active sensors (PWAS) attached to the monitored structure. Present-day impedance analyzer equipments (e.g.HP4194) are bulky, heavy and expensive lab...

Piezoelectric materials constitute a class of intelligent materials that are helpful for monitoring the structural integrity. The principle of the piezoelectric impedance-based structural health monitoring technique is to measure the electrical impedance of a piezoelectric patch attached to a structure in a certain frequency range. Electrical impedance variations indicate physical changes in th...

In recent years, impedance measurement method by piezoelectric (PZT) wafer activesensor (PWAS) has been widely adopted for non-destructive evaluation (NDE). In this method, theelectrical impedance of a bonded PWAS is used to detect a structural defect. The electro-mechanicalcoupling of PZT materials constructs the original principle of this method. Accordingly, the electricalimpedance of PWAS c...

Intelligent piezoelectric materials are helpful for monitoring the structural health. The principle of the piezoelectric impedance-based structural health monitoring (SHM) technique is to measure the electrical impedance of a piezoelectric patch attached to a structure in a certain frequency range. Electrical impedance variations indicate physical changes in the structure indirectly due to coup...

This paper presents an overview and recent advances in impedance-based structural health monitoring. The basic principle behind this technique is to apply high-frequency structural excitations (typically greater than 30kHz) through surface-bonded piezoelectric transducers, and measure the impedance of structures by monitoring the current and voltage applied to the piezoelectric transducers. Cha...

Deployment of structural health monitoring systems for permanent damage detection is limited by the availability of sensor technology. The development of a DSP based prototype is the focus for initial efforts in realizing a fully self-contained active sensor system utilizing impedance-based structural health monitoring. The active sensing system interrogates a structure utilizing a self-sensing...

In almost all practical field applications, the structure that is being monitored is constantly undergoing changes due to external boundary and environmental conditions. This change, in most cases, is considered to be normal and a part of the everyday use of the structure. Examples of the factors that lead to this change are loading of the structure, vibration of the structure and change in the...