EngineerMember of ASTM, Mechanical Technology, Inc., Latham, N.Y.
ManagerMember of ASTM, Mechanics of Materials Unit, Materials and Processes Laboratory, General Electric Co., Schenectady, N.Y.
A fracture mechanics model is developed to describe crack growth in a low cycle fatigue test specimen. The model involves a J integral analysis and a growth rate hypothesis in terms of ΔJ. A relationship for low cycle fatigue is derived that has strain energy density as the controlling variable. This relationship reduces to well-known low cycle fatigue equations in terms of elastic and plastic strains for the limiting conditions of fully elastic and fully plastic strain fields. These equations in turn define relationships between the material properties commonly employed to describe low cycle fatigue and fatigue crack growth rate data. The latter are used to demonstrate the facility of predicting fatigue crack growth rate curves from standard low cycle fatigue properties.
Paper ID: JTE10223J