A CMOD-Based Hybrid Approach to Determine Fracture Resistance Curve

This study proposes a hybrid approach that relies both on the numerically computed and on the experimentally measured load (P) versus the crack-mouth opening displacement (CMOD) relationships to derive the fracture resistance curve (J-R curve) for the mixed-mode I and II fracture specimen. The CMOD-based hybrid approach utilizes a single experimental specimen with a growing crack and multiple finite element (FE) models, each with a different crack depth. The experimental procedure measures the P-CMOD curve from a standard fracture specimen with a growing crack. The intersections between the experimental P-CMOD curve and the numerical P-CMOD curves from multiple FE models dictate the CMOD levels to compute the strain energy (U). This approach simplifies the J-R curve test for the single-edge-notched bend, SE(B), specimen by eliminating the multiple unloading and reloading procedures in determining the variation of the compliance during the test. This method also provides an alternative simple measurement of the J-R curves for mixed-mode I and II specimens. The validation procedure shows accurate predictions of the J-R curves for both SE(B) specimens and mixed-mode I and II specimens.