Structural fatigue crack detection by using admittance of embedded piezoelectric patches

摘要

In this paper, a method for on-line fatigue crack detection based on self-sensing piezoelectric patches is presented. When piezoelectric patches are electronically excited, they cause stress in the structure to which they are attached. The existence of crack causes reducing the natural frequencies which are sensed by the admittance of the transducer. By measuring the peak frequencies of electric admittance of the patches, the natural frequencies of the cracked beam can be obtained. Based on the changes of natural frequencies of the beam, a steady-state genetic algorithms is applied to identify the detection of damage. A free-free beam containing a crack is given as an example. The experimental results show that it is accurate to detect the crack location and crack depth.