Vol.4, No3, 2004, pp. 137-148
 UDC 678.7-19.017  666.188.21:666.22

NUMERICAL AND EXPERIMENTAL ANALYSIS OF INITIAL FAILURE OF COMPOSITE LAMINATES WITH EMBEDDED FIBREOPTIC SENSORS

Irena Živković 1

Stevan Maksimović 2

Radoslav Aleksić 3

1 Institut bezbednosti, Kraljice Ane bb, Belgrade

2 Military Technicak Institute, Katanićeva 15, Belgrade

3 Faculty of Technology and Metallurgy, University of Belgrade

Abstract

Phenomenon of initial failure of laminar composite materials under static loading is studied in this paper by using numerical simulation based on finite element method (FEM) on one side, and experimental method applying fibre optic sensors (FOS) on the other side. Procedure has been conducted on the group of improved thermoplastic ballistic composite materials – para-aramid fibre – poly (vinyl butiral) of increased toughness. This thermoplastic laminar composite shows about 5.5 times higher capability of energy absorption compared to recently used materials with the same reinforcement. Numerical simulation of this material behaviour with embedded fibre optic sensor under static indentation is performed using criteria for determination of the initial failure time, e.g. loading level which causes failure of the first layer in laminated composite structures. For the analysis of stress and strain distribution within laminate composite structure under indentor pressure, 3-D FEM analysis is applied to simulate the projectile/composite plate contact problem. The results of FEM analysis of considered composite plate have shown good agreement with the experiment regarding the detection of loading level which initiates failure, including “communication” of composite structure with optical fibres.

Keywords: damage monitoring, thermoplastic composite materials, intensity-based fibre optic sensors, indentation, FEM

full article (621 kB)