Une approche multi-physique du soudage en continu des composites à matrice thermoplastique : vers une modélisation multi-échelle

The automated tow placement process allows fabricating thermoplastic composite parts by welding of pre-impregnated plies. The adhesion between plies, which induces the mechanical properties at the interface, is governed by three coupled physical phenomena: i) the inter-diffusion of macromolecules at the interface when the polymer is melted, ii) the crystallisation of the matrix, which can be partial when the cooling rate is very high, iii) the degradation of the polymer at high temperature, which induces crosslinks. An explicit 2D finite differences model has been performed to take these three phenomena into account. The heat transfer coefficients have been determined by an inverse method from thermal measurements. The local temperature fields have been predicted at the interface and the process conditions window has been established. Mots-clefs : soudage, diffusion des macromolecules, simulation multi-echelles