Failure diagrams for subcritical crack growth

•Failure diagrams help assess the possibility of failure of a component in service load conditions.•A predictive methodology is required to assess component failures for subcritical crack growth under cyclic, static, or combined loads.•Modified Kitagawa-Takahashi diagram is used to develop the failure diagrams for cyclic, static, and combined loads.•The two-parametric nature of fatigue is explored without the need for any crack closure to assess the crack growth leading to failure.•The analysis is extended to include short crack growth without invoking any similitude breakdown. Failure diagrams help evaluate safe use, require monitoring or replacement of structural components subjected to service loads based on the material properties. They are commonly used in the pipeline industry as failure assessment diagrams based on the fracture toughness data and Yield Stress. Failure diagrams could help evaluate the fatigue life or crack growth leading to failure of a component subject to fluctuating loads experienced during the service environment. Understanding the subcritical crack growth behavior, its quantification, and application to components in service are essential. In the following, basic understanding and the development of these failure diagrams using Kitagawa-Takahashi plots and the two-parametric approach that we have developed in the past are discussed, taking several examples from the literature.