Design Against Fatigue

TARGET

1. Educate the basics of design and calculation of mechanical parts and structures against fatigue damage and fracture.
2. Educate the basic theory of the Finite Element Method, modeling and calculation of simple machine parts

CONTENT

• Static and cyclic characterization of materials, hysteresis loop.
• Fatigue stress-life curves, fatigue strain-life curves, mean stress effect – Haigh’s and Smith’s diagrams.
• Stress concentration, notch factor, cracks and stress intensity factor, other fatigue degradation factors.
• Design of machine parts for unlimited life, safety factor, probability of fracture.
• Decomposition of stochastic process, Rain-flow method, loading histograms (loading spectra), experimental verification of fatigue life.
• Fatigue damage, accumulation of damage, linear and nonlinear damage hypothesis (Miner’s rule, Corten-Dolan, SWT – parameter)
• Approaches for fatigue life prediction. Design of machine parts for limited life, safety factor, probability of fracture.
• Basic of fracture mechanics and crack growth under cyclic loading.
• Thermal fatigue. Crack corrosion cracking. Creep and combination with fatigue.

• Minimum of potential energy approach in structural/continuum mechanics. Examples of rods and beams.
• Essentials of matrix algebra and matrix formulation of simple bar structure. Finite element formulation of the structure.
• General finite element method. Discretization of 2D continuum, element and global operators, mechanical and thermal loads.
• Finite element discretization of 2D and 3D continuum, axisymmetric structures.
• Utilization of FEA in modeling of parts and assemblies of structures.

Study materials

1. Suresh, S.: Fatigue of Materials. Cambridge Univ. Press, 2nd ed., 1998. ISBN 0 521 57046 8
2. Stephens, R.I-Fatemi, A.- Stephens R.R. and Fuchs, H.O: Metal fatigue in engineering, Wiley-Interscience, 2nd ed., 2000, ISBN:978-0471510598
3. Bathe, K. J.:Finite Element Procedures, Prentice Hall, New Jersey, 1996
4. Zienkiewicz, O.C.-Taylor, R.L.: The Finite Element Method. Fifth Edition, Butterworth-Heinemann, 2000, ISBN:0 7506 5049 4