Temperature effects on an acoustic emission based SHM system - Applied to composite materials

Temperature effects on an acoustic emission based SHM system - Applied to composite materials

Vargalui, A.
Martinez, M.J.
Zarouchas, D.
Pant, S.

Aerospace Engineering

Aerospace Structures and Materials

2015-12-31

This study focuses on understanding the effect of temperature variations and the position of the piezoelectric sensors with respect to fiber orientation angle, as it relates to acoustic emission wave velocity in composite structures. A hybrid panel consisting of Unidirectional Carbon Fiber (UDCF) combined with Unidirectional Glass Fiber (UDGF) along with foam-core sandwich panels with hybrid face-sheets were used for this case study. The group velocities of ultrasonic Lamb waves for three different temperatures (-40 °C, +25 °C and +70 °C) at three different positions (0°, 45° and 90° with respect to the fiber direction) were measured using an Acoustic Emission (AE) system. In order to perform the experiments, a special set-up was built consisting of an environmental chamber and a temperature cycling unit. In parallel, a Finite Element Model (FEM) was developed to simulate the wave propagation of several signals in the three aforementioned temperatures. An analytical algorithm found in the literature was used to verify the experimental results. The main findings of this work were that the Lamb wave group velocities are affected by the fiber orientation more than by temperature variations imposed on the system. In addition, it was found that the signals propagate 15 to 20 % faster in the hybrid laminate than the sandwich panel.

http://resolver.tudelft.nl/uuid:c4ea36be-e5fa-400b-b734-58bfeadcc2de

Proceedings of the 26th International Conference on Adaptive Structures and Technologies ICAST, Kobe (Japan) 13-16 Oct. 2015

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conference paper

(c)2015 The Authors