Detecting Damage in Composite Material Using Nonlinear Elastic Wave Spectroscopy Methods

Abstract

Modern aerospace structures make increasing use of fibre reinforced plastic composites, due to their high specific mechanical properties. However, due to their brittleness, low velocity impact can cause delaminations beneath the surface, while the surface may appear to be undamaged upon visual inspection. Such damage is called barely visible impact damage (BVID). Such internal damages lead to significant reduction in local strengths and ultimately could lead to catastrophic failures. It is therefore important to detect and monitor damages in high loaded composite components to receive an early warning for a well timed maintenance of the aircraft. Non-linear ultrasonic spectroscopy methods are promising damage detection and material characterization tools. In this paper, two different non-linear elastic wave spectroscopy (NEWS) methods are presented: single mode nonlinear resonance ultrasound (NRUS) and nonlinear wave modulation technique (NWMS). The NEWS methods were applied to detect delamination damage due to low velocity impact (<12 J) on various composite plates. The results showed that the proposed methodology appear to be highly sensitive to the presence of damage with very promising future NDT and structural health monitoring applications.

Non destructive evaluation of bi-material structures: a case study

“…The objective here is to analyze these nonlinear effects in order to provide a quantification of the non-linear acoustic transmission which is related to the damage state and its severity in the bi-polymer material. Generally, there are two main types of NEWS: [10][11][12] resonance and non-resonance based methods. The present paper focuses specifically on the non-resonance methods that analyze the modulation spectrum.…”

Inherent acoustic nonlinearity of fiber reinforced composites

“…They called this class of materials as mesoscopic materials where the elastic behavior was controlled by mesoscopic elements along the grain boundary. Following this, several researchers have used NEWS techniques to detect and quantify damage in composites and other materials [10][11][12][13][14][15][16][17][18][19]. Van Den Abeele demonstrated the use of NEWS techniques for detecting damage in fiber cemented plates.…”

“…The hysteresis behavior along with non-classical nonlinear indicators were summarized [10,11]. Impact damage in composite laminates and sandwich panels was investigated by Meo [14,15]. Micro-crack density from heat damage was quantified using a nonlinear parameter by Van den Abeele [16].…”

“…This would lead one to believe that composites may exhibit mesoscopic behavior similar to rocks and concrete. The present study does not explore the possibilities of using nonlinear acoustic methods for damage detection in composites since it has been performed by various researchers [14][15][16][17][18][19]. Rather, it focuses on studying the inherent baseline nonlinearity of fiber-reinforced composites, which is the nonlinear response of the material in its intact or undamaged state.…”

Nonlinear Time Reversal Focusing and Detection of Fatigue Crack

“…In more recent years, nonlinear elastic wave spectroscopy (NEWS) methods have been introduced to assess nonlinear elastic effects of damaged materials [15][16][17][18]. NEWS is a set of techniques to determine the existence and degree of nonlinearity in elastic systems.…”