A time reversal focusing based impact imaging method and its evaluation on complex composite structures

Abstract

The growing use of composite structures in aerospace structures has attracted much interest in structural health monitoring (SHM) for the localization of impact positions due to their poor impact resistance properties. The propagation mechanism and the frequency dispersion features of signals on complex composite structures are more complicated than those on simple composite plates. In this paper, a time reversal focusing based impact imaging method for impact localization of complex composite structures is proposed. A complex Shannon wavelet transform is adopted to extract frequency narrow-band signals of impact response signals of a PZT sensors array at a special time-frequency scale and to measure the phase velocity of the signals. The frequency narrow-band signals are synthesized using software, depending on the time reversal focusing principle, to generate an impact image to estimate the impact position. A demonstration system is built on a composite panel with many bolt holes and stiffeners on an aircraft wing box to validate this method. The validating results show that the method can estimate the position of impact efficiently.

Structural Health Monitoring for Composite Materials

“…where 12 L For plate-like structures, modal AE (MAE) [50][51][52] is often presented based on elastic wave theory. In MAE, AE signal is analyzed in terms of different propagating wave modes, among which the basic A0 and S0 modes are mostly concerned.…”

“…The experiment system is built on the top panel of the carbon fiber composite material. An array of smart layers [52] with three PZT wafers is attached on the inner surface of the top panel. Four impacts are produced to the plate using a hammer (seen in figure 20).…”

A model-based approach for statistical assessment of detection and localization performance of guided wave–based imaging techniques

“…Structural Health Monitoring (SHM) techniques can reduce maintenance costs significantly by switching from the schedule-based maintenance to a condition-based maintenance, and by allowing the use of lighter materials such as composite or sandwich panel in the case of aerospace structures [1]. SHM has been studied for decades, leading to the development of a large panel of techniques [2,3,4,5,6,7,8,9,10,11,12,13,14,15]. Among them, techniques based on guided wave (GW) propagation with piezoceramic transducers are cost-effective and allow a quick on-demand inspection of large areas over thin metallic and composite structures [16].…”

Impact Localization Method for Composite Plate Based on Low Sampling Rate Embedded Fiber Bragg Grating Sensors

“…And the most common active method is the time reversal method. The main idea of time reversal method is to reverse the receiving signal and then output it in the sensor node; thus the signal will focus on the impact position [19][20][21]. This method only needs few priors and sensors, but active sensors and accurate TDOA are indispensable.…”