| Abstract: | Environment assisted fracturing, or stress corrosion cracking of adhesive joints in liquid water or a humid atmosphere was shown to occur at values of applied crack extension force ?a considerably below those required for onset of opening-mode rapid fracture ?c. The minimum value of ?a below which no cracking was observed, ?SSC, was dependent on the relative humidity and the particular adhesive used. For two adhesive systems, the one with the lower hardener content and post cure temperature showed both a lower absolute value of ?SSC and a lower ratio of ?SSC to ?c. The value of ?SSC for both adhesive systems decreased as the humidity was increased. As the relative humidity approached 100%, the value of ?SSC approached its value for liquid water. Values of ?c for the two adhesives differed by a ratio of approximately 2:1. When water was introduced to the crack tip, ?c for the less tough material increased while it was not significantly changed for the tougher material. |
