Design Against Fatigue (E111069)

Katedra: | ústav mechaniky, biomech.a mechatr. (12105) | ||

Zkratka: | Schválen: | 08.06.2010 | |

Platí do: | ?? | Rozsah: | 1P+1C |

Semestr: | * | Kredity: | 2 |

Zakončení: | Z,ZK | Jazyk výuky: | EN |

Anotace

The subject provides students with fundamentals of both engineering approach to failure under cyclic loading - fatigue, and finite element analysis. Fatigue and FEA lectures are separated, students has to apply these methods to solve operational life and safety of simple part at homework example.

Osnova

FATIGUE

- Fatigue phenomenon: Wohler curve, stationary load cycles, stress/strain life curves. Stress concentration: shape factor, notch sensitivity and notch factors; load, surface, treatment and size influence. Mean stress influence: Haigh's/Smith's diagrams, equivalent stress amplitude. Faigue damage cummulation. Probability of failure.

FEM

Deformation and force approach, principle of virtual displacements, principle of total potential minimum (Lagrange's principle) - all by hinged bar structure example. Generalization of the principles in continuum. Vector spaces and Ritz's method explanation using tension-compression example with goniometric and/or piecevise linear base functions. Finite element method as particular case of Ritz's method.

- Fatigue phenomenon: Wohler curve, stationary load cycles, stress/strain life curves. Stress concentration: shape factor, notch sensitivity and notch factors; load, surface, treatment and size influence. Mean stress influence: Haigh's/Smith's diagrams, equivalent stress amplitude. Faigue damage cummulation. Probability of failure.

FEM

Deformation and force approach, principle of virtual displacements, principle of total potential minimum (Lagrange's principle) - all by hinged bar structure example. Generalization of the principles in continuum. Vector spaces and Ritz's method explanation using tension-compression example with goniometric and/or piecevise linear base functions. Finite element method as particular case of Ritz's method.

Osnova cvičení

No excercises. To pass an assignment student has to solve homework - calculation of durability and probability of failure of simple shaped (planar or axisymmetric) notched part under tension or bending stationary cyclic load. The shape factor of notch has to be determined using both literar resources and finite element analysis.

Literatura

Lecturers's slides and other resources are placed in http://moodle.fs.cvut.cz under "Automotive Engineering" -> "European Master of Automotive Engineering" -> "Design against fatigue". This site requires CTU Id and password.

Požadavky

Fundamentals of engineering mechanics of deformable bodies: understanding displacements, strain and stress components, Hook's law, strain energy, basic tension, bending and torsion theories. Fundamentals of matrix algebra and calculus.

Klíčová slova

Fatigue, durability, reliability, variational principles in mechanics, FEA