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.