Coffin-Manson model
In materials engineering, the Coffin-Manson relationship describes the course of the strain Wöhler curve in the low-cycle fatigue range (LCF), i.e. in the range from 1 to 10 5 cycles . In this area, components are so heavily stressed that plastic deformations occur in the cycle . According to Coffin and Manson, in the LCF area i. W. determining the plastic strain amplitude :
- .
- = Coefficient of fatigue ductility , corresponds roughly to the true elongation at break (in the quasi-static tensile test).
- = Fatigue ductility; for ductile materials applies: .
- = Number of cycles until break .
A double logarithmic plot results in a falling straight line, with the ordinate now plotting on the ordinate compared to the normal Wöhler diagram.
See also
literature
- Ralf Bürgel, Hans Jürgen Maier, Thomas Niendorf: Handbook high temperature materials technology: Fundamentals, material stresses , high temperature alloys and coatings , Springer Fachmedien Wiesbaden, Wiesbaden 2015, ISBN 978-3-658-10591-4 , pp. 196-200