Temperature-dependent thermal expansion behaviors of carbon fiber/epoxy plain woven composites: Experimental and numerical studies

Thermal expansion behaviors of carbon fiber/epoxy plain woven composites were experimentally and numerically studied in this paper. The thermal strains and linear coefficient of thermal expansion (CTE) of plain woven composites were measured by a classic dilatometer. Based on the periodical displacement and temperature boundary conditions, two-scale finite element models, i.e. the micro-scale and meso-scale representative volume elements (RVEs) were established to analyze the thermal expansion behaviors of carbon fiber yarns and plain woven composites, respectively. In addition, a neat epoxy resin (NER) model with the same geometrical shape as the filled epoxy resin (FER) was presented to compare their thermal expansion differences. From the results it could be found that the glass transition temperatures of epoxy resin and carbon fiber yarns had significant effects on the thermal expansion behaviors of plain woven composites. The interlacing network of yarns could effectively restrict the FER to make further thermal expansion. The special structure effects of plain woven composites led to nonuniform distributions of thermal stress/strain, which mainly showed that the regions with higher fiber volume fraction produced higher thermal stress/strain. The analyses methods this paper presented can be also used for thermal expansion researches of other complex structure composites.