Fatigue crack growth (FCG) is a major cause of failure in many engineering components and structures that are subjected to dynamic loading conditions. Several models have been proposed for estimating crack growth rate da/dN under various conditions. The majority of work reported has focused on constant amplitude (CA) loading and some for variable amplitude (VA) loading. The estimation of da/dN under VA loading is complex due to effects of several factors such as plasticity, crack tip blunting, residual stresses, crack tip closure and crack tip branching which are associated with different levels of loading. These factors which cause acceleration or deceleration of the crack growth are known as interaction effects. Crack closure has been identified to be one of the main interaction factors, and finite element (FE) models have been developed to quantify it in terms of crack opening stresses. There are however still a number of issues regarding the modelling parameters such as mesh size, element type, number of loading increments and material hardening models that should be used and on whether crack closure represents the interaction effects sufficiently. Also modelling long crack lengths has been perceived to be too computationally intensive and therefore studies focus on short crack lengths only.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:496022 |
| Date | January 2009 |
| Creators | Aguilar-Espinosa, Aaron Alejandro |
| Publisher | Oxford Brookes University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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