Continuous-time, high-cycle fatigue model for nonproportional stress with validation for 7075-T6 aluminum alloy
Stefan B. Lindström
Abstract
The continuous-time, high-cycle fatigue model of Ottosen et al. (2008) is modified by introducing a quadratic, instead of linear, endurance surface. This quadratic endurance surface induces an elliptical Haigh diagram, consistent with experimental fatigue data for ductile materials. With this modification we fit the model to uniaxial fatigue data, and predict the fatigue behavior for nonproportional, biaxial stress for AA7075-T6 in fully reversed shear with a superimposed, static tension/compression. However, the fatigue life is sometimes overestimated for a combination out-of-phase shear and tensile stress fluctuations.
Topics & Concepts
Materials scienceAluminiumUltimate tensile strengthQuadratic equationShear stressStress (linguistics)Fatigue testingStructural engineeringShear (geology)Compression (physics)AlloyFatigue limitComposite materialEngineeringMathematicsGeometryLinguisticsPhilosophyMetal Forming Simulation TechniquesFatigue and fracture mechanicsMetallurgy and Material Forming