A COMPARATIVE STUDY OF CRACK CLOSURE AND ENERGY BASED CONCEPTS

摘要

The fatigue crack growth behavior of the Aluminum alloy 2024 is analyzed using the crack closure and an energy based concept. It is shown that most of the effects usually attributed to closure can be successfully explained using energy concepts. In particular, it is shown that there exists a linear relationship between the crack growth rate and the energy dissipated per cycle at high growth rates and it corresponds to a crack growth mechanism characterized by striation formation during each cycle. For lower growth rates a power law relationship can be proposed between these two parameters. The above mentioned linear relationship holds good also for the block loading conditions based on total energy dissipated per block.