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EM 520 - Fracture Mechanics (Mecānica da Fractura)
1. Linear elastic fracture mechanics - LEFM. Crack tip stress analysis. Stress intensity factor K. Energy based methods. Strain energy release rate G. Relationship between K and G. K computation using the finite element method. Plastic region at the crack tip. Plane strain and plane stress. Equivalent elastic crack. Plane strain fracture toughness KIc. ASTM E399 standard. 2. Elasto-plastic fracture mechanics. Dugdale model. Crack opening displacement - tests and standards. The Welding Institute design curve. J integral. Relationship J - COD. 3. Stable crack growth: fatigue and stress corrosion. Paris law, fatigue crack growth threshold. Relationship between SN tests (Wohler) and fracture mechanics based fatigue studies. 4. Application of fracture mechanics to composite materials. 5. Failure analysis. CEGB R6 criterion. Objectives This course seeks to provide concepts and tools for the evaluation of the structural integrity of constructions, and for the prevention and analysis of failures. |