Averaged strain energy density criterion to predict ductile failure of U-notched Al 6061-T6 plates under mixed mode loading

Notch ductile failure with significant strain‐hardening: The modified equivalent material concept

“…The calculation process of the tensile strength value for the equivalent material in MEMC is absolutely the same as that in EMC . In the previous works, a power‐law expression has been used to relate stress to strain in the plastic region, and the closed‐form expression for the tensile strength of the equivalent material, σ f * , has been proposed as follows: …”

“…By considering the values of the main parameters E , ε u , true , K , n, and σ y , for the tested Al 5083 to be 67 GPa, 0.013, 451 MPa, 0.09, and 225 MPa, respectively, the value of σ f * is calculated to be equal to 680 MPa. More details dealing with EMC can be found in the literature …”

“…In the literature and some other research works dealing with EMC, it can be clearly found that EMC has been based on an important assumption that a valid fracture thoughness (ie, K Ic or K c ) exists for the ductile material which can be obtained according to ASTM E399 . Such an assumption has been shown to be satisfied in those ductile materials, for which the ultimate and yield strengths are not so different . Because of needing ductile materials with considerable strain‐hardening in design process of engineering structures, eg, the sheet metals in automobile and ship structures etc., LCC prediction for such materials weakened by notches of various shapes is necessary.…”

Application of EMC‐J criterion to fracture prediction of U‐notched polymeric specimens with nonlinear behaviour

“…Thus, the tensile strength of the equivalent material (σ * f ) can be evaluated by the following formulation [23][24][25] : Initially, 2 assumptions have been made to formulate the elastic-plastic behaviour of a real ductile material to the linear-elastic behaviour of a virtual brittle material till the fracture moment 21 : The tensile strength of the equivalent material has been calculated by combining the power-law equation which considers plastic behaviour of the real ductile material using the stress-strain relationship and the SED formulation for brittle materials at the point when the crack growth commences.…”

“…26,27 the EMC has been linked to the MTS and MS criteria, providing the 2 ductile failure prediction models, called EMC-MTS and EMC-MS. [23][24][25] Cicero and co-researchers 16 have tested PMMA SENB weakened by U-notches and loaded under symmetric 3-point bending, experienced considerable plastic deformations around their notch border. As a successful fracture criterion, the ASED criterion has been used by some researchers to evaluate the brittle fracture of cracked and notched samples made of different brittle and quasi-brittle materials (eg, rocks, polymers, and graphite).…”