Experimental and numerical investigations of a thermoplastic composite (carbon/PPS) thermoforming

For lightweight structural components, continuous fibre-reinforced thermoplastic composites have demonstrated success in aerospace and defence applications. Their mechanical behaviour is a result of the possible sliding and interactions between the fibres, but the complex deformation mechanisms of this sheet are a main problem in the practical thermoforming process. In this context, a large experimental work was developed to analyse the behaviour of a 5-harness satin weave carbon–polyphenylenesulfide (PPS) composite. Firstly, we started this work with a microscope observation of the sheet cross section and a thermo-gravimetric analysis of carbon/PPS to understand the thermal condition in the forming process, the reinforcement (fibre and yarn) geometry and dimensions and the textile reinforcement architectures. Secondly, in high temperature conditions (at 320�C), static uniaxial and biaxial tensile tests were carried out. During these mechanical tests, we used a digital image stereo-correlation technique to get full field displacement measurements and an infrared camera to measure the temperature in the surface of sample. The results of the experimental investigation were used with the commercial software ABAQUS to develop a numerical model of stamp thermoforming operation. The stamp thermoforming part was developed using a hemispherical punch and compared with an experimental result. In the deformed part obtained by thermoforming of the carbon/PPS sheet, we analysed the instability phenomena such as wrinkling

X-ray tomography analysis of the mechanical behaviour of reinforcements in composites

International audienceX-ray tomography is a non-destructive technique which allows reconstruction of the internal geometry of opaque and massive materials in three dimensions (3D). This chapter first discusses the capabilities of this technique in the field of the mechanics of composite reinforcements. It then describes methods of analysing reconstructed data at different characteristic length scales. The chapter also includes an example of the use of such analyses to develop a numerical model of the mechanical behaviour of a woven composite reinforcement