Piezoceramic-based 2D Spiral Array and Multiple Actuators for Structural Health Monitoring: Thin Isotropic Panel with Straight Boundaries

Abstract

A new and robust 2D phased array technique with multiple distributed actuators is experimentally studied for damage detection in a thin isotropic panel. This array technique is combined with guided Lamb wave (GLW) interrogation. A 2D phased array technique using a single actuator, located near the center of the array, is unable to detect a linear crack whose orientation is normal to the wavefront of the GLW excited from the actuator. To overcome this limitation, the array is coupled with multiple actuators positioned at four different locations on a test panel, while the array is mounted at the center of the panel. A piezoceramic-based 2D spiral phased array is used as a sensor array. The associated array signal processing is used to produce array responses and detect two types of damages, such as a rubber patch and linear crack. An innovative GLW propagation and reflection analysis method is implemented to evaluate the damage locations within the panel geometry. Experimental results demonstrate that the spiral array damage detection technique, using multiple distributed actuators, can provide more robust damage detection scheme, in thin isotropic panels, than the array technique with a single actuator collocated at the center of the array.