Investigations into Temperature and Specimen Geometry Dependence of the 'Local Approach' Parameters of a Structural Steel

TWI Industrial Member Report Summary 513/1995

C S Wiesner

Background

The 'Local Approach' is a micro-mechanical failure model in which cleavage fracture is predicted to take place when a critical stress state is reached in the region of interest. The method has been shown to be a powerful tool to predict cleavage fracture for a wide range of configurations, including the effect of constraint, etc. One area which has been identified as needing further attention is the question of whether the 'Local Approach' parameters, m and

Sixty notched tensile and 61 Charpy-type notched bend specimens were tested at lower shelf temperatures (-196°C<T<-130°C). The tests were processed using finite element and statistical analyses to determine the 'Local Approach' parameters. A limited study was also made regarding the influence of the statistical method and the number of tests on the values of the parameters. From the results and their discussion, the following conclusions and recommendations are made: