The Notch and Size Effect in Brittle-Ductile Transition Behaviour of Materials

Abstract

The reliability and life time of engineering structures are determined by the external and internal local stress-strain concentrators. The internal stress-strain concentrators are caused by microstructure inhomogenities of materials, the external ones by notches. It is obvious that it is not possible to design a construction without considering the effects of stress-strain concentrators. The behaviour of local zones at notches is determined by the notch geometry, loading conditions and the local material response. From the engineering point of view the so called “notch effect” is very important both in brittletransition behaviour and in fatigue failure of structural components because 90% of the failures are initiated by the stress-strain concentrators. Considering the statistical data that each countries loses the app. 4% of the GDP by failures, so the notch effect in engineering practice is a very important issues from the economical point of view as well.