Exploration of irreversible residual stresses in a carbon/epoxy composite

Residual stresses in composite material may rise from several sources; difference in thermal straining between fibre and matrix, chemical shrinkage of the matrix material. The presented paper explores an irreversible Eigen-strain in the material which is shown to change and be removed by a thermal treatment above the Tg of the matrix material. This has been observed though TMA measurements of a carbon/epoxy unidirectional sample. The local Eigen-strain is translated into stresses using a visco-elastic constitutive relation. Further exploration indicates that cooling rate influence the generation of residual stresses in the material.