A manufacturing imperfection: fiber distortion and its effect on thermomechanical properties of polymer composites

Abstract

The aim of this study is to investigate the effect of a production imperfection, fiber distortions, on the resulting thermoelastic behaviour of composite materials in hexagonally packed Representative Volume Elements (RVEs) with finite elements micromechanical modelling. Instantaneous thermochemical and thermoelastic behavior of resin throughout the cure cycle is implemented into the model. This enables to calculate the resulting thermomechanical properties of composites, having fiber distortions from 0 to 18%, at the end of the cure cycle. It is found that the fiber distortion has great effect on the process induced residual stresses and Coefficients of Thermal Expansion (CTE) values. Equations expressing the variation of residual stresses and CTEs with fiber distortion are obtained. This study proves the importance of consideration of fiber distortions, a manufacturing defect, in finite element modeling of composite materials.

Keywords

• composite materials
• imperfection
• fiber distortion
• thermomechanical properties
• kompozit malzemeler
• imalat kusuru
• fiber bozulması (distorsiyon)
• thermomekanik özellikler