This work focused the analysis of hygrothermal ageing effects on the tensile strength of thermoset laminated composites. Humidity and temperature effects on the longitudinal and transversal tensile strengths of carbon fiber/epoxy 8552 unidirectional laminates tape composites ([0/0]s) were investigated. The longitudinal tensile strength results at room temperature was not significantly affected by exposing the samples to either the humidity-controlled chamber or the salt spray chamber. However, the specimens submitted to the humidity-controlled chamber and tested at elevated temperature (80 °C and 90% RH) presented a decrease in the longitudinal tensile strength. A small decrease in the transversal tensile strength results was observed during room temperature tests in the samples submitted to salt spray chamber. A higher decrease in the transversal tensile strength was verified in the samples submitted to the humidity-chamber. Samples submitted to the salt spray chamber tested at elevated temperature showed a small decrease in the transversal tensile strength (11%). A drastic reduction in the strength (51%) was observed in the samples submitted to the humidity-chamber and tested at high temperature. A fractograph study by scanning electronic microscopy (SEM) was performed in every single sample involved in the tests. These results highlight that the elevated temperatures affect the polymeric matrix.
Carbon-fiber; epoxy laminate composite; hygrothermal ageing; tensile properties
