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Proceedings Paper

Simulation of ultrasonic NCF composites testing using 3D finite element model
Author(s): Z. Liu; N. Saffari; P. Fromme
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Paper Abstract

Composite materials offer many advantages for aerospace applications, e.g., good strength to weight ratio. Different types of composites, such as non-crimp fabrics (NCF), are currently being investigated as they offer reduced manufacturing costs and improved damage tolerance as compared to traditional pre-impregnated composite materials. NCF composites are made from stitched fiber bundles (tows), which typically have a width and thickness in the order of millimeter. This results in strongly inhomogeneous and anisotropic material properties. Different types of manufacturing imperfections, such as porosity, resin pockets, tow crimp and misalignment can lead to reduced material strength and thus to defects following excessive loads or impact, e.g. fracture and delaminations. The ultrasonic non-destructive testing of NCF composites is difficult, as the tow size is comparable to the wavelength, leading to multiple scattering in this inherently three-dimensional structure. For typical material properties and geometry of an NCF composite, a full three-dimensional Finite Element (FE) model has been developed in ABAQUS. The propagation of longitudinal ultrasonic waves has been simulated and the effect of multiple scattering at the fiber tows investigated. The effect of porosity as a typical manufacturing imperfection has been considered. The potential for the detection and quantification of such defects is discussed based on the observed influence on the ultrasonic wave propagation and attenuation.

Paper Details

Date Published: 20 April 2012
PDF: 8 pages
Proc. SPIE 8348, Health Monitoring of Structural and Biological Systems 2012, 83481F (20 April 2012); doi: 10.1117/12.915195
Show Author Affiliations
Z. Liu, Beijing Univ. of Technology (China)
N. Saffari, Univ. College London (United Kingdom)
P. Fromme, Univ. College London (United Kingdom)

Published in SPIE Proceedings Vol. 8348:
Health Monitoring of Structural and Biological Systems 2012
Tribikram Kundu, Editor(s)

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