Lamb wave attenuation study through delamination in a WGF/epoxy composites, numerical and experimental investigation

Shafiei Alavijeh, Maryam; Shahid Beheshti University; Iran

Alavijeh, M.S.; Shahid Beheshti University; Iran
Soorgee, M.H.; Shahid Beheshti University; Iran

ID: ECNDT-0293-2018
Session: Composite Material - UT 3
Room: G1
Date: 2018-06-14
Time: 16:20 - 16:40

Composite structures have gained much attention in several industries due to their high specific strength, light weight, resistance to fatigue/corrosion and flexibility. However, these structures are susceptible to various types of damages during manufacturing process as well as in-service use, including cracks, voids, delamination and etc. So health monitoring of such structures is of interest. In this paper a 4-layer woven glass fiber reinforced epoxy (WGF/epoxy) composite plate has been investigated for delamination detection via ultrasonic Lamb waves. Dispersion curves of specific composite plate have been extracted using semi-analytical finite element method (SAFEM) in order to extract phase and group velocities. Having done the dispersion analysis, both S0 and A0 modes at low dispersive region of the curves have been selected to be used for inspection. The plate has been simulated as a 2D finite element (FE) model in ABAQUS/Explicit. A delamination has been applied between 2nd and 3rd layers. Actuation signals with different frequencies have been applied to the plate and interaction of Lamb mode with delamination has been captured via forward and backward scattered wave field’s signals. Moreover, an experimental setup has been built up for Lab scale tests. It is observed that increasing the frequency from 100 KHz to 300 KHz for the 4-layer WGF/epoxy plate leads to decrease in transmitted signals amplitude. A heat generating contact model at delamination region has been employed to predict wave attenuation due to contact surfaces interaction and finally it is shown that numerical results that gotten from the model with mentioned contact model matches experiments closely.