Fatigue crack growth under variable-amplitude loading: Part Ⅱ- Code development and model validation

摘要

A state-space model of fatigue crack growth has been formulated based on the crack closure concept in the first part of the two-part paper. Th unique feature of this state-space model is that the constitutive equation for crack-opening stress is governed by a low-order non-linear difference equation without the need for storage of a long load history. Therefore, savings in the computation time and memory requirements are significant. This paper, which is the second Part, provides information for code development and validates the state-space model with fatigue test data for different Types of variable-amplitude and spectrum loading in 7075-T6 and 2024-T3 aluminum alloys, respectively. Predictions of The state-space model are compared with those of the FASTRAN and AFGROW codes.