Moisture Effect on the Interlaminar Resistance of Woven Fabric Thermoplastic Composite

In the present study, the effect of moisture on the interlaminar fracture toughness of two woven fabric composite materials has been investigated. The composites used are made of a woven fabric 8H Satin glass fiber and 8H Satin carbon fiber. The matrix is a polyetherimide (PEI). The composites are used in aeronautical and aerospace applications. The interlaminar fracture behavior is analyzed using the mode I, double cantilever beam (DCB) test, and the mode II, end notched flexure (ENF), in order to determine the energy required for the initiation and growth of an artificial crack. The composites are subjected to a relative humidity (95%) and a constant temperature (70° C) in a climatic chamber for 30, 60, 120, and 180 days. The delamination energies are calculated using the corrected beam, Berry theories, and the experimental calibration method at the characteristic points. The result shows that the decrease in the fracture behavior is more important in the material CD342 8H Satin weave. The fracture mechanism was also analyzed by means of scanning electron microscopy.