Fiber bragg grating based detection of part-thickness cracks in bent composite laminates using feature-guided waves

Abstract

Composite structures with bends are widely used in aerospace and industrial sectors. However health monitoring of such structures is challenging due to their complex topographical features. Recent literature shows that bends in composite laminates can confine and guide ultrasonic energy along their length, known as feature-guided waves (FGW). This article demonstrates a fiber Bragg grating based technique using FGW modes for defect detection and identification in bent composite laminates. In addition, the effects of defect depth and excitation frequency on the FGW mode reflection coefficient are reported using 3D finite element simulations. Physical insight into the reflection behavior is discussed based on an analysis of mode interaction with part-thickness cracks.

Statistics-based baseline-free approach for rapid inspection of delamination in composite structures using ultrasonic guided waves

“…Structural Health Monitoring (SHM) based on ultrasonic guided waves is attractive for long range inspections of large scale and complex composite structures. [1][2][3][4][5][6] An early approach in guided wave SHM compares signals from the structure under operation with the baseline obtained at 'time 0'. [7][8][9] Recently, there has been considerable interest in outlier-based approaches which rely on a threshold value calculated from the baseline data.…”

Outlier analysis for defect detection using sparse sampling in guided wave structural health monitoring

“…Defect identification and localization has also been recently demonstrated by wave visualization using non‐contact reception at multiple locations for a fixed excitation 12,13 . In general, Lamb waves are widely discussed for delamination detection, and the authors have also published extensively on Lamb wave‐based detection of delamination in simple and complex composite structures 4,7,13,13‐17 . This paper is set in the context of reduction of sensor density for Lamb wave‐based SHM approaches.…”

Mode excitability and selectivity for enhancing scanning guided wave-based characterization of subwavelength defect

“…Exploiting the defect-induced disturbance in linear features and nonlinear features of probing GUWs, one can diagnose diverse material anomalies and evaluate the structural health condition qualitatively and quantitatively [9][10][11][12]. Nevertheless, the further improvement of the sensitivity of existing methods (linear or nonlinear) are limited by diverse factors related with the intrinsic features of GUWs.…”