ENCE151
Strength of Materials
Syllabus
- Simple Stress and Strain (10 hours)
- Introduction to Strength of Materials
- Deformable bodies, external forces, internal stresses and strains
- Types of stresses: Normal stress, shear stress, bearing stress
- Material behavior under axial loading: Stress-strain diagram for mild steel, yield stress, proportional limit, elastic limit, Hooke's law, Young's modulus of elasticity, strain hardening, ultimate stress/strength, ductility, toughness, elastic and inelastic strains, concept of factor of safety and allowable/permissible stress
- Stress-strain behavior for ductile and brittle materials, proof stress
- Fatigue and creep strength
- Thermal stress and strain in simple, compound, composite and indeterminate bars
- Lateral strains and Poisson's ratio
- Shear deformation and shear angle; Hooke's law for shearing deformations, modulus of rigidity
- Multi-axial loading and generalized Hooke's law
- Definitions of isotropic, anisotropic and orthotropic materials
- Volumetric stress-strain, bulk modulus
- Relationships between elastic constants
- Saint-Venant's principle and stress concentrations
- Elongation of bars under axial loadings: Uniform and varying cross sections, tapered sections, compound and composite bars
- Use of compatibility equations for axially loaded indeterminate bars
- Geometric Properties of Sections (5 hours)
- Axes of symmetry
- Centre of gravity of plane and built-up sections
- Moment of inertia of standard and built-up sections
- Parallel and perpendicular axis theorems
- Polar moment of inertia
- Radius of gyration
- Product moment of inertia
- Principal axes and principal moment of inertia
- Mohr's circle for principal moment of inertia
- Principal Stress Analysis in 2D Planes (5 hours)
- Stresses in inclined plane: Normal stress under uniaxial loading, Normal and shear stress subjected to two mutually perpendicular planes
- Principal planes and principal stresses
- Relationships between normal and shear stresses
- Maximum shear stresses
- Mohr's circle diagram for principal stresses
- Principal Strain Analysis (4 hours)
- Plane strain: Normal and shear strains in inclined planes
- Principal strains, maximum in-plane shear strains and their positions
- Mohr's circle diagram for plane strain
- Absolute maximum shear strain
- Strain rosettes
- Modes of failure for different materials
- Introduction of failure theories
- Thin Walled Vessels (3 hours)
- Introduction and characteristics
- Types of stresses and strains in cylindrical and spherical pressure vessels
- Calculation of stresses and strains in pressure vessels
- Torsion (5 hours)
- Introduction to torsion
- Stress-strain behavior in torsion
- Derivation of torsion formula for a circular shaft
- Torsional moments: Series and parallel combination of shafts and composite shaft
- Torsional stress in shafts, torsional resilience
- Comparison between solid and hollow shafts
- Power transmitted by shafts
- Statically indeterminate shafts
- Introduction to non-circular shafts
- Combined bending and torsion
- Theory of Flexure (8 hours)
- Introduction to flexure
- Coplanar and pure bending
- Derivation of bending equation
- Distribution of bending stress across the different beam cross-sections
- Analysis of beams for symmetric and composite sections
- Shear equation, shear stress variation in rectangular, circular, I and T sections
- Concept of slope and deflection in beams using double integration method: Simply supported and cantilever beams
- Column Theory (5 hours)
- Introduction: Buckling and stability of columns
- Classification based on slenderness ratio
- Effect of support conditions and effective length
- Derivation of Euler's formula for different end conditions, limitations and applicability
- Intermediate columns: Rankine's hypothesis
- Introduction to uniaxial and biaxial eccentric loading, condition for no tension
Practicals
- Tensile test and stress-strain curve for mild steel bar, HYSD bar, timber
- CG of simple plane figure
- Simple bending test on timber, steel, aluminum beams: Deflection, flexural relations and MoI comparisons
- Torsion test on simple shaft to determine modulus of rigidity
- Test on column behavior and buckling