Experimental study of impact localization in aluminum plates using Taguchi method

Abstract

Several internal defect types can have an impact on structural performance and shorten its lifetime. Structural Health Monitoring (SHM) proposes a viable alternative by integrating a set of sensors for continuous structure monitoring. This enables early detection of the initiation and propagation of structural damage. Sensors permanent integration requires first determining their best placement, to ensure that a large area of the structure is monitored. However, using many sensors to cover a large area can have a negative impact on the structure's weight and thus, its performance. Hence, the main objective of this paper is to design an optimal sensor grid for acoustic source localization in plates using a network of four sensors along with triangulation algorithm. This work aims to validate experimentally the technique and to suggest a new procedure for implementing sensor networks for impact localization. The procedure is based on robust design methodology and sensor positions are determined based on the optimization of an objective function using the Taguchi SN ratio.

A 400x400x2 mm aluminum plate is used herein, and the impact is generated by dropping a small steel ball at its center. Impact signals are acquired by piezoelectric sensors bonded to the plate's surface and captured by a four-channel oscilloscope. The efficiency of the proposed approach has been proved and the optimized sensor network located the impact with an error of 0.46 %.