Real-time impact identification algorithm for composite structures using fiber Bragg grating sensors

Abstract

In composite structures, low-velocity impact-induced damage such as delamination are mostly hidden inside laminates or leave a small dent on the impact side. Thus, detecting this type of damage using conventional inspection methods is not easy and requires much time and cost. To enhance efficiency of these methods, information on the estimated impact locations must be provided with a high accuracy. In this way, unnecessary inspections for large intact regions can be reduced. In this study, impact localization algorithms for various composite structures were developed using the impact induced acoustic signals acquired by multiplexed fiber Bragg grating (FBG) sensors. The acoustic waves from a given impact were transmitted to each FBG sensor, and incurred FBG wavelength shifts were captured by a high speed multiplexible FBG interrogation system with a sampling frequency of 100 kHz. After acquisition of the FBG sensor signals at all the training points in the target section, the impact wave arrival time differences between each FBG signal were calculated to produce the input data sets for neural network training. To reliably use the neural network algorithm for impact identification, high reproducible arrival time determination algorithms are essentially required. In this study, such arrival time determination algorithms were developed through various types of structures. Finally, we evaluated the performances of the suggested impact identification algorithms for a composite wing box structure.

Ultrasonic Excitation – Fiber Bragg Grating Sensing Technique for Damage Identification

“…Tsuda et al verifies fiber Bragg grating (FBG) response sensitivity for ultrasonic wave on the composite materials [4]. Jang, Byeong-Wook uses multiplexed FBG sensor to study positioning algorithm for composite structures [5]. Muthumari reviews of various ultrasonic techniques employed in modern industries [6].…”

Strain Wave Acquisition by a Fiber Optic Coherent Sensor for Impact Monitoring

“…This includes, on one hand, load monitoring, that identifies extreme load scenarios like those related to impacts, and on the other hand, damage identification, e.g. due to fatigue ageing or corrosion [1][2][3][4][5], that includes anomaly detection, damage type evaluation, localization, quantification and the final prognosis of its future evolution.…”

“…The first method, namely the passive monitoring [2][3][4][5], consists in the identification of an impact by analyzing the time-series data generated by the impact itself, which provide information about impact occurrence, its location and force, often referred to as impact force reconstruction [6]. The second…”

Low Velocity Impact Localization on CFRP Based on FBG Sensors and ELM Algorithm

“…The intelligent algorithm generally include neural network and vector machines, etc. Worden and Staszewski [7] and Jang et al [8] used neural network algorithm to locate the impact position. However, in their research, a large set of reference data and high speed FBG interrogation techniques exceeding 100 kHz are needed.…”