IENTIFICATION AND QUANTIFICATION OF RESIDUAL STRAINS DURING CURING OF CARBON FIBER EPOXY LAMINATES

摘要

Residual strains develop from matrix shrinkage and non-isotropic coefficients of thermal expansion in composite laminates throughout the cure cycle. These strains influence the final shape and strength of the laminate. It is hypothesized that cure strains depend on lamina orientation, lamina stacking sequence, spatial location, and cure kinetics. In the present study, embedded strain gages are used to monitor residual strain development. Changes in strain due to elevated temperature post cure are quantified and a study of the curing epoxy characteristics is performed using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). These later studies provide insight to the measured internal laminate stresses and provide guidance in the interpretation of the strain measurements.