Damage detection in composite materials using Lamb wave methods

Abstract

Cost-effective and reliable damage detection is critical for the utilization of composite materials. This paper presents part of an experimental and analytical survey of candidate methods for in-situ damage detection of composite materials. Experimental results are presented for the application of Lamb wave techniques to quasiisotropic graphite/epoxy test specimens containing representative damage modes, including delamination, transverse ply cracks and through-holes. Linear wave scans were performed on narrow laminated specimens and sandwich beams with various cores by monitoring the transmitted waves with piezoceramic sensors (PZT). Optimal actuator and sensor configurations were devised through experimentation, and various types of driving signals were explored. These experiments provided a procedure capable of easily and accurately determining the time-of-flight of a Lamb wave pulse between an actuator and sensor. Lamb wave techniques provide more information about damage presence and severity than previously tested methods (frequency response techniques), and provide the possibility of determining damage location due to their local response nature. These methods may prove suitable for structural health monitoring applications since they travel long distances and can be applied with conformable piezoelectric actuators and sensors that require little power.

Early damage detection in epoxy matrix using cyclobutane-based polymers

“…The measurements of the E/M impedance or admittance signatures are related to the mechanical impedance which is affected by the presence of damage. Lamb wave method is also suitable for structural health monitoring applications [12][13] .…”

Nonlinear System Identification for Damage Detection

“…An alternate approach is to identify features that directly compare the sensor waveforms or spectra of these waveforms measured before and after damage. Many of the features identified for impedance-based and wave propagation-based SHM studies fall into this category [5,6,7,8].…”

Multidimensional guided wave dispersion recovery for locating defects in composite materials

“…Yet, while composites provide many advantages, assessing their structural health is a significant challenge. Structural defects can manifest in many forms, including delaminations between layers [3], cracking in the epoxy matrix [4,5], damage to individual fibers [6], porosity [7,8], voids [8], and fiber waviness [9,10,11]. These defects can occur during manufacturing or inservice operation and can significantly weaken the structure.…”