Factors Controlling the Strength of Composite Structures.
Final rept. 1 Mar 69-28 Feb 70,
MATERIALS RESEARCH LAB INC GLENWOOD IL
Pagination or Media Count:
Measurements are made of the fracture toughness and stress corrosion cracking characteristics of adhesive joints consisting of the epoxy resin-DER 332 hardened with either TEPA or HHPA. The following are found the range of toughnesses obtained by varying hardener content and post-cure temperature is broader for the amine than for the anhydride hardened joints, but the mean of the two ranges is approximately the same the anhydride hardened joints are more sensitive to water than the amine ones and both fracture toughness and resistance to stress corrosion cracking increase with joint thickness to a maximum for very thick joints. High values of fracture toughness are associated with a macro-roughening of the fracture surface, but the increased resistance to stress corrosion cracking is not. The fracture toughness and stress corrosion cracking of commercial adhesives, either scrim or particle filled, are also discussed. Finally, the design of a self- stressed specimen for studying stress corrosion cracking is described. Author-PL
- Adhesives, Seals and Binders
- Couplers, Fasteners and Joints