FIBER REINFORCED COMPOSITES
Micro-indentation : quantitative analysis of the interface's behaviour


     The fiber/matrix interface plays an essential part in the mechanical behaviour, fatigue life and durability of fiber-reinforced composite materials.

One of our research team developed a simple micro-indentation test allowing the mechanical characterisation of such an interface: a glass fiber (diameter 2r, Young modulus E=73000 MPa) is indented in its matrix (Young modulus 3000 MPa) by a Vickers indenter, providing curves of the applied load P according to the indenter's penetration u0.

A shear-lag model has been developed in order to quantitatively analyse those indentation curves, giving:
- a parameter n which characterises the material around the tested fiber: it particularly depends on the fiber packing and it's regularity
This parameter gives access to the local stiffness k of the system : n=(k/rE)½

- the interfacial debonding stress td

- the debonding length h at the interface versus the applied load
  the length H over which sliding happens during the indentation unloading
We propose here an applet to visualize the micro-indentation test. The user will follow an inverse process: one will first choose a fiber of diameter 2r with a characteristic debonding stress td at the interface and a stiffness k of the system.
By appliying a cycle of load P (by clicking on the scrollbar you will get incrementations of 0.1N until a threshold of 1N) one can visualize the load P/penetration u0 curve and get the values of h and H during a cycle.



See the following publication upon which is based the applet:

Quantitative analysis of the micro-indentation behaviour of fibre reinforced composites: development and validation of an analytical model
Mondher Zidi (a,b), Luc Carpentier (b), Antoine Chateauminois (c), François Sidoroff (b)
Composites Science and Technology - Elsevier
(a) Laboratoire de Mécanique des Solides, Ecole Nationale d'Ingénieurs de Monastir, Tunisie
(b) Laboratoire de Tribologie et Dynamique des Systèmes (LTDS), UMR CNRS 5513, Ecole Centrale de Lyon, France
(c) Laboratoire d'Ingénierie et Fonctionnalisation des Systèmes (IFoS), UMR CNRS 5621, Ecole Centrale de Lyon, France

version française Summary


Authors : Marie-Hélène Levé and Antoine Chateauminois  - Ecole Centrale de Lyon - June 2000