DCAMM Seminar - Mechanism of Failure in Fatigue and Tribology from Viewpoint of Small Defects and Small Cracks

A DCAMM seminar will be presented by

Professor Yukitaka Murakami
Kyushu University, Japan 

Abstract:

1. Fatigue
Some important types of microstructural defects which are detrimental to fatigue strength will be illustrated and discussed in terms of      their size, position, shape, orientation and properties, together with their effect on the fatigue resistance of a material. This will be coupled with a fracture mechanics approach that quantifies their behavior in terms of their relationship to fatigue crack propagation. The boundary condition between failure and non-failure is explored using fracture mechanics as a theoretical condition for a small crack coupled with the Vickers hardness HV of the material that represents the threshold condition (ΔK_th).
Directions for optimizing microstructure to improve fatigue strength are explained from the viewpoint of quality control based on the statistics of extremes of defects and inclusions.

2. Tribology
Tribology damages so-called pitting and spalling are always originated from a small defect. However, tribology problems have not been  well studied from the viewpoint of fracture mechanics. In this lecture, experimental and fracture mechanics study of the pit formation mechanism under contact fatigue is presented focusing on the effect of reversal of rotation and change of the driving roller.
The measurement of ΔK_IIth and ΔK_IIIth for several steels and its applications will be presented.

Danish pastry, coffee and tea will be served 15 minutes before the seminar starts.
  
All interested persons are invited