Abstract
The crack-tip constraint is defined as the resistance of a structure to plastic deformation around the crack tip. It can affect the fracture toughness significantly. A loss of crack-tip constraint can cause an increase in fracture toughness. To make the best use of the low-constraint components and reduce over-conservatism in structural integrity assessment, it is important to find a method to assess the changes in crack-tip constraint and the variation of fracture toughness it caused.In this dissertation, a unified constraint parameter λ based on the plastic strain energy was proposed and validated experimentally and numerically. The studies involved three materials, BS 1501-224 steel, Al7075 T651 and A516 G70 steel. A large number of different-type specimens with a wide range of geometries were tested under different temperatures. The comparisons between several wide-accepted constraint parameters and parameter λ were investigated.
| Date of Award | 4 Feb 2025 |
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| Original language | English |
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| Supervisor | Mahmoud Mostafavi (Supervisor) |