Analysis of experimental factors in elastic–plastic small specimen mixed-mode I-II fracture mechanical testing

The quality of experimental fracture resistance testing results in mixed-mode I-II loading is more than questionable in several cases. This study describes efforts to gain consistent results with respect to mixed-mode I-II fracture resistance curve determination when working with elastic–plastic materials. The entire mixed-mode I-II field is evaluated, i.e. both numerical and experimental factors are considered the focus being on the asymmetric four-point bend set-up. Several error prone features are presented, and minimization of their effects on quantitative fracture resistance assessment considered. The results indicate that through a careful evaluation of the stages in experimental testing and numerical analysis valid, material characterizing, fracture toughness results can be obtained.