Measurements of strain induced by chemical shrinkage in polymer composites

Abstract

Abstract The aim of this work is to determine which of the techniques that allow to measure the strain induced in polymer composites by the chemical shrinkage of resin is most appropriate for predicting process-induced deformations. There are two approaches to determine the chemical strain: measurements in-plane and through-the-thickness of composite. In the following study, two methods were used for the measurement of unidirectional carbon/epoxy composite: novel one that employs a dynamic mechanical analyzer to measure through-the-thickness strain and one designed previously to measure in-plane strain. As the results of the methods were different, finite element simulation of process-induced deformation of C-sectioned composite element was carried out in order to verify the results. Comparison of numerical results with the real part deformation showed that the measurement of through-the-thickness chemical strain is the more accurate approach in the case of the prediction of deformation and that the novel method gives valid results.