No abstract

For the application of continuous fibre-reinforced thermoplastics in car body structures it has to be ensured that they can pass through the automotive paint shop. There are substantial chemical, hygroscopic and thermal impacts throughout this process that can affect the shape of such components. The aim of this study is to model the deformation behaviour of continuous fibre-reinforced thermoplastics under hygrothermal loading. Relaxation tests were performed to assess temperature-dependent and viscoelastic behaviour. Input parameters for temperature and moisture distribution were determined experimentally and computed using finite difference method. A straightforward approach based on classical laminate theory is presented that comprises anisotropic viscoelasticity as well as hygroscopic, thermal and polymer-chemical effects. The introduced phenomenological model was successfully used to describe the deformation of five different laminate layups both dry and fully saturated with moisture.

This paper presents results of material characterisation experiments on the hygrothermal viscoelastic behaviour of unidirectional laminates of continuous carbon-fibre reinforced polyamide 6. The material behaviour when subjected to the automotive painting process is of interest.Coefficients of thermal-and -moisture expansion were determined from dilatometer experiments and micrometer measurements together with weighing, respectively. Diffusion coefficients were generated from thermogravimetric analysis and fitted with the Arrhenius equation. Dynamic mechanical analysis and digital image correlation of quasi-static tensile tests were performed to obtain a relaxation curve and a major Poisson's ratio, respectively. The Williams-Landel-Ferry equation was fitted to the time shift factors.