Skip to main content
European Commission logo print header

IMPROVEMENT OF QUALITY CONTROL BY REMOTE MONITORING OF FIBRES ORIENTATION IN INJECTION MOULDED POLYMER COMPOSITES

Obiettivo


In this project several non-destructive evaluation (NDE) methods were tested to explore how well they are suited to monitor and resolve in-depth fibre orientation in polymer composites, more specifically in injection moulded thermoplastics composites. Different types of composite materials were processed with either continuous fibres or short fibres to provide samples with either well controlled or unknown fibre orientation. Both destructive fibre orientation characterization (by implementing scanning force microscopy) and mechanical testing were finally performed on a series of Round Robin test samples in order to assess the potential of the NDE methods for quality control.

It turned out that four NDE methods could be candidates for successful applications in industrial environment. First of them relies on the analysis of the thermal field induced by local heating of the composite surface and has two variants: thermal ellipsometry and lock-in thermography. As they are only sensitive to the thermal anisotropy generated by the particular fibre orientation, the fibres have to be more thermally conductive than the matrix. Thermal methods are thus efficient only in the presence of carbon fibres. An other remote method, i.e. microwaves transmission is applicable to all non-conducting fibres. Due to the same constraint regarding transmission, the light scattering method can only be successful if the matrix-filler system and the respective concentrations are such that light passes through the inspected material. The last method (ultrasonics) has the disadvantage of requiring liquid coupling to the inspected part. However, it responds to all kinds of fibres.

These methods are capable not only to display depth averaged orientation fields but also to indicate (at least to some degree) how orientation changes with depth.
The strength of polymer composites depends critically on their fibres orientation. While fibres orientation can be monitored easily in long fibres materials,this control proves to be difficult for injection moulded short fibre composites. The aim of this project is thus to develop non destructive evaluation (NDE) methods for the fibres orientation remote monitoring in such materials. The filler orientation characterization will have to resolved in depth. The tool defined during this project will help to optimize component design and production parameters.

The main tasks of the proposed work are:

- preparation of representative samples of short fibre reinforced composites by injection moulding;

- application of different nondestructive evaluation (NDE) methods (laser thermography,microwaves and light scattering,speckle analysis, dielectric spectroscopy,ultrasonic propagation analysis), inversion of the experimental signals in order to extract from them the fibres orientation distribution;

- destructive evaluation of the samples in view of a macroscopic and a microscopic description;

- assessment of precision and versatility of the different NDE methods; correlations of their respective results and the samples quality defined via mechanical test.

This project could be pursed towards the integration of the retained NDE method(s) in a closed loop for the process optimization in order to obtain a maximum of safety and strength of the moulded structure for the intended application.

Invito a presentare proposte

Data not available

Meccanismo di finanziamento

CSC - Cost-sharing contracts

Coordinatore

Office National d'Etudes et de Recherches Aerospatiales - ONERA
Contributo UE
Nessun dato
Indirizzo
29, avenue de la Division Leclerc
2320 CHATILLON
Francia

Mostra sulla mappa

Collegamenti
Costo totale
Nessun dato

Partecipanti (4)