SEDL / STP / STP937-EB / STP24373S

Micromechanisms of Fracture in Toughened Graphite-Epoxy Laminates

Jordan, WM
Research assistant and professor of mechanical engineering, Texas A&M University, College Station, TX

Bradley, WL
Research assistant and professor of mechanical engineering, Texas A&M University, College Station, TX

Pages: 20    Published: Jan 1987

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Abstract

The combination of low cross-link density and elastomer additions has been seen to give the most potent toughening for neat resins. A relatively small increment of the additional neat resin fracture toughening above 800 J/m² is actually reflected in the delamination fracture toughness of a composite. Mode II delamination toughness of brittle systems may be as much as three times the Mode I delamination fracture toughness, while a ductile system may have a Mode II delamination fracture toughness that is similar to the Mode I value. The energy absorbed per unit area of crack extension for delamination seems to be independent of ply orientation if proper accounting of the near and far field energy dissipation is made.