Experimental Investigation of Impact Localization in Composite Plate Using Newly Developed Imaging Method

Abstract

This paper focuses on impact localization of composite structures, which possess more complexity in the guided wave propagation due to the anisotropic behavior of composite materials. In this work, a composite plate was manufactured by using a compression molding process with proper pressure and temperature cycle. Eight layers of woven composite prepreg were used to manufacture the composite plate. A structural health monitoring (SHM) technique was implemented with piezoelectric wafer active sensors (PWAS) to detect and localize the impact on the plate. There were two types of impact event that were considered in this paper (a) low energy impact event (b) high energy impact event. Two clusters of sensors recorded the guided acoustic waves generated from the impact. The acoustic signals were then analyzed using a wavelet transform based time-frequency analysis. The proposed SHM technique successfully detected and localized the impact event on the plate. The experimentally measured impact locations were compared with the actual impact locations. An immersion ultrasonic scanning method was used to visualize the composite plate before and after the impact event. A high frequency 10 MHz 1-inch focused transducer was used to scan the plate in the immersion tank. Scanning results showed that there was no visible manufacturing damage in the composite plate. However, clear impact damage was observed after the high-energy impact event.

Recent Advances in Piezoelectric Wafer Active Sensors for Structural Health Monitoring Applications

“…A network of PWAS transducers and the damage imaging method were used to detect and quantify the delamination in the cross-ply composite plate. In recent work [70,71], an improved imaging method was developed to obtain accurate results of localization and sizing damages in metallic plates and composite laminates. Here, some more recent results in this direction are presented.…”

“…Here, some more recent results in this direction are presented. The gist of our methodology [70,71] is to perform a point-by-point detection and localization of damage as a first step before using the imaging methods. Four sensors are distributed to make a cross sign on the area of interest.…”

Impact localization and force reconstruction for composite plates based on virtual time reversal processing with time-domain spectral finite element method

“…12 In the case of impact localization, the time of fight (ToF) or time of arrival (ToA) of transducers are effective indicators for locating the impact position. 13 This strategy utilizes the velocity of waves induced by the impact and coordinates of sensors to detect the impact source geometrically. Qiu et al 14 extracted narrow-band signals from impact responses by the continuous complex 1 School of Astronautics, Northwestern Polytechnical University, Xi'an, China 2 Shannon wavelet transform, in which the responses are broadband signals.…”

Numerical and experimental investigation of delamination severity estimation using local vibration techniques

“…Four damage factors based on modal parameters were analyzed by evaluating pristine and damaged cases (Pérez et al, 2014). The piezoelectric sensor wafer (PWAS) represents one of the typical transducers used in SHM applications (Haider et al, 2018; Migot and Giurgiutiu, 2017). Vibration-based model approaches incorporating PWAS transducers into the composite structure are a practical solution for meeting such objectives.…”