The Effects of Hygrothermal Aging on Mode II Delamination Propagation in G40-800/5276-1 Graphite/Epoxy Composite

摘要

This paper presents the results of an experimental investigation of the effects of long term hygrothermal exposure on mode II delamination propagation in G40-800/5276-1, an aerospace grade graphite/epoxy composite. In this study, unidirectional [0]_16 composite specimens were conditioned by immersion in water at 70 °C for a ten month period, during which effective saturation was attained. The delamination propagation characteristics of these specimens, i.e., delamination toughness (G_Ⅱc) and fatigue delamination growth rate (da/dN) were obtained using four-point bend end notch flexure (4ENF), a test configuration that results in stable delamination propagation. When compared with 'dry' specimens, the 'wet' specimens suffered a loss in G_Ⅱc and an increase in da/dN. Also, the number of cycle for delamination onset was lower in wet specimens.