Fatigue Analysis of a Simple Shaft under （下一个简单的轴的疲劳分析）.pdf

Fatigue Analysis of a Simple Shaft under Combined Bending and Torsion Material baseado em exemplo da HBM-nCODE e Ansys PRESENTATION TOPICS • Introduction • SAE notched shaft Specimen • Geometry and FEM model • Boundary Conditions • Linear Static Analysis Results • Overview: Fatigue Life Estimation • Conclusion • References and Used Software Introduction Courtesy nCode Introduction Aloha Airlines Flight 243 (1988) Introduction • Fatigue life is estimated based on crack initiation method. • A notched shaft under combined bending and torsion loads is analised. • Two loading are combined , each load with its own loading history. • Linear stresses used for the calculation is obtained from bending and torsion loading independently. SAE notched shaft specimen • Standard SAE notched shaft [1] is modeled. • This kind of specimen was used [1] to produce experimental results for multiaxial fatigue ,and later, these results were compared to 5 different theories to estimate life to multiaxial fatigue (not the scope of this example). Geometry Finite Element Model: Mesh Boundary Condition: Fixed Support Boundary Condition: Force Boundary Condition: Moment Linear Static Structural Analysis • Two static analysis were performed – Bending due to unitary force – Torsion with a moment of 1000 N.mm – Following slides present stress distribution and dispacements Results: Applied load is unitary force Von Mises Equivalent Stress Displacements Maximum Principal Stress Results: Applied load is a Moment Von Mises Equivalent Stress