A computational study of AE signal due to fiber break and fiber matrix debonding in model composite

Abstract

Acoustic emission monitoring is a useful method to deal with detection and identification of damage in composite materials during mechanical tests. From an experimental point of view, it is not straightforward to establish a quantitative link between the damage sources and AE signals. Modeling and numerical simulations appear as a promising way to reach this objective. In this study, Finite Elements Modeling (FEM) was used to simulate AE signals due to fiber break and fiber/matrix debonding in a model carbon fiber composite. A specimen made of a single carbon fiber and epoxy matrix was used to experimentally validate the simulated fiber break AE signals. The objective was to compare the AE signals from a validated fiber break simulation (Fig. 1a) to the AE signals obtained from fiber/matrix debonding (with several models) and fiber break obtained in several media and to discuss the capability to detect and identify each source (Fig. 1b). The influence of the type of sensor, specimen geometry and AE source location were also studied. The proposed model was extended to identify the main parameters that influence the acoustic emission signatures. These validated results open the way to combine the experimental and the simulated data to generate a library in order to identify real-time damage mechanisms. Fig. 1: (a) Amplitude and roll-off frequency vs. source/sensor distance for experimental signals and numerical signals. (b)Evolution of Partial Power PP1 [0–125 kHz] as a function of amplitude obtained with a nano 30 sensor for several sources. Fiber break and debonding (L = 20 μm or 100 μm). EWGAE 35, Ljubljana, Slovenia, 13th – 16th Sep. www.ewg