Quantification of notch effects -: In brittle-ductile transition

In the presents paper notch effects on brittle to ductile transition behaviour of steels and its description has been followed. Based on experimentally measured data for mild steel and data from literature local parameters, the notch stress, strain and energy intensity factors, respectively have been introduced arising from the global stress, strain or deformation energy fields (gradients) and characteristic distances. The relationships between the notch intensity factors and the notch radius in 1/K vs. rootrho co-ordinates are linear for stress and strain fields and non-linear (parabolic) for deformation energy. The brittle to ductile transition sensitivity of materials can be characterised by the slope of the curves obtained. The experimental results performed at -196 degreesC on notched tensile specimens made of mild steel with different grain size are in full agreement with presented concept and they can be regarded as an experimental verification of the proposed approach.