Review of fatigue crack propagation models for metallic components (original) (raw)

The prediction of fatigue properties of structures and avoiding structural fatigue were recognized as engineering problems in the early decades of the 20th century. A practical problem also associated with variable amplitude loading was the question of how long old structures could still be used without running into fatigue problems. In the second half of the previous century, this question was raised for old bridges and aircrafts. Although a general understanding of many aspects of fatigue crack growth behavior was established in the early 1960s, a specific 'accumulation of damage model' for computation of growth under a wide variety of service loads was lacking. Various service load damage models were proposed in the 1970s which at best successfully augmented extensive testing under simulated service load conditions. Questions emerging from the above picture are associated with the reliability and accuracy of prediction models and the physical concept of fatigue damage. This paper reviews the fatigue life models as a scientific and engineering knowledge about fatigue of material and structures, which includes fatigue life prediction models under constant and variable amplitude loading. The selection of the appropriate model is usually based on the analyst's experience and persona1 preference. The review leads to an inventory of the present state of the art and some final remarks follow in an epilogue.