Equivalent Stress Intensity Factor: The Consequences of the Lack of a Unique Definition

The concept of an equivalent stress intensity factor Keq is used in the study fatigue crack growth mixed-mode situations. A problem seldom discussed research literature are consequences coexistence several alternative definitions mixed mode Keq, leading to rather different results associated with definitions. This note highlights problem, considering hitherto not analyzed simultaneously. Values calculated according criteria were compared through determination Keq/KI over a wide range values KI/KII or KII/KI. In earlier work on Al alloy AA6082 T6, path and rate measured 4-point bend specimens subjected asymmetrical loading compact tension modified holes. presentation data was made using Paris law based Keq. Important differences found laws, corresponding considered, requirements for candidate discussed. perspective overcoming shortcomings may consist developing data-driven modelling methodology, supported by material characterization structure monitoring during its life cycle.