Font Size: 

The reliability and life-time of engineering structures are determined by theexternal and internal local stress, strain concentrators. The internal stress, strainconcentrators are caused by microstructure inhomogenities of materials, the external ones bynotches. It is obvious that it is not possible to design a construction without considering theeffects of stress, strain concentrators. The behaviour of local areas at notches is determined bythe notch geometry, loading conditions and the local material responses. From theengineering point of view the so called "notch effect" is very important both in brittletransitionbehaviour and in fatigue failure of structural elements because 90% of the failuresare initiated by the stress-strain concentrators. Considering the statistical data that eachcountries loses the app. 4% of the GDP by failures, so the „notch effect in engineeringpractice” is a very important issues from the economical point of wives as well. This paperattempt to join the concepts of the linear fracture mechanics and the notch mechanics bydefining the notch-stress, notch-strain and notch-energy intensity factors.