The course extends knowledge provided in MECHENG 242, to the analysis of 3D states of stress and strain, with an initial focus on elasticity. Non-linear material behaviour is introduced, considering yield and plasticity. Knowledge of material strength is deepened; considering yield theories for ductile materials, fracture mechanics of brittle materials, and fatigue. Application is made to mechanical elements, including complex beams, and axi-symmetric systems (thick-walled pressure vessels). Numerical analysis is introduced, with students applying Finite Element Analysis to mechanical elements, via a computer-based laboratory and an assignment.
Mechanics of Materials
States of stress and strain at a point; analysis of stress under conditions of plane stress and plane strain; strain rosettes; generalised stress-strain relationships for linearly elastic and isotropic materials. Theories of yield.
Introduction to Numerical Methods
Introduction to Finite Element Analysis (FEA), including principles of computation. FEA model development. Results interpretation and validation.
Machine Elements: Beams
Asymmetrical or skew bending. Thin-walled open sections and shear centre.
Machine Elements: Thick-walled Pressure Vessels
Stresses and strains in axi-symmetric systems, as applied to thick-walled pressure cylinders. Initial yield and plastic collapse in pressure vessels.
Non-linear Stress-strain Behaviour
Non-linear elasticity. Elementary plasticity, and yield theories for ductile materials.
Fracture in Brittle Materials
Stress concentration due to geometric features. Failure mechanisms in brittle materials. Introduction to linear elastic fracture mechanics; fracture toughness. Crack growth under repeated or cyclic loading.
Fatigue in Ductile Materials
Introduction to material fatigue. Environmental and design influences. Fatigue under uni-axial and multi-axial stress states. Cumulative damage.