On the Point Method load-bearing capacity predictions in Al7075-T651 structural components containing stress risers

This paper presents the Theory of Critical Distances (TCDs), and more precisely, the Point Method (PM), as a methodology for the prediction of the load-bearing capacity of structural components containing any kind of stress risers and subjected to static conditions. The main aim is to validate this application in Al7075-T651 specimens with different types of defects, geometries and loading conditions, beyond its application to fracture mechanics specimens, covering the different situations appearing in structural components. It is also intended to analyse those situations where the TCD provides accurate results and those where this is not the case, as well as to provide criteria about the predictive capacity of the TCD. The results show that the PM provides accurate results as long as the Neuber number, defined as the notch radius divided by the critical distance (L), is sufficiently low (20 is taken as a reference value). If it is intended to extend the validity limits of the PM to situations where the Neuber number is higher, it is then necessary to include in the calibration process of L fracture notched specimens with similar radii to those being analysed, and to use the value of L which provides the corresponding lower envelope of the experimental calibration results (here called LLE).

► An experimental programme has been developed in Al7075-T651 in order to validate the Point Method.
► The results validate the application of the PM in the prediction of the load-bearing capacity.
► Such application is satisfactory provided the Neuber number is limited to 20.
► The extension of this validity range requires an alternative calibration process.