Damage Tolerance Assessment of Bonded Repairs to CF-18 Composite Components. Part 1. Adhesive Properties

摘要

The damage tolerance properties of three epoxy adhesives used in the manufacture and repair of the composite structure on the CF-18 aircraft are assessed. The resistance to both static fracture and fatigue crack growth are evaluated. Experimental variables include the mode of fracture (tension and shear), the fatigue load ratio, the test temperature and the method of bonding. Both the static and fatigue tests were found to rank the adhesives in the same order, viz. FM-300K superior to FM-300 superior to EA-9321. The fatigue testing revealed a tendency for delamination type failures to occur at low temperature, a situation likely to lead to nonconservative joint designs. The fatigue crack growth rate data are explained in terms of the failure mechanisms observed. The implication of these findings to the selection of repair adhesives for composite aircraft structure is discussed. Jet aircraft, Canada. (JES)