Mechanical Properties Quiz

Mechanical Properties

• Deals with the behavior of materials under applied forces
• Focuses on how materials deform and fail under load

Stresses and Strains

• Stress: Force acting per unit area within a deformable body
• Strain: The deformation of a material caused by stress
• Direct Stress (Normal Stress): Force acting perpendicular to a cross-sectional area
• Shear Stress (Tangential Stress): Force acting parallel to a cross-sectional area

Stress-Strain Relations

• Elasticity: Ability of a material to return to its original shape after the stress is removed
• Plasticity: Ability of a material to undergo permanent deformation after the stress is removed
• Stress-Strain Diagrams: Visualize material behavior under loading

Biaxial and Triaxial Loading

• Biaxial: Loading in two mutually perpendicular directions (e.g., a thin plate with stresses in two directions)
• Triaxial: Loading in three mutually perpendicular directions (e.g., a block subjected to pressure)

Elastic Constants

• Young's Modulus (E): Ratio of stress to strain in the elastic region
• Shear Modulus (G): Ratio of shear stress to shear strain in the elastic region
• Poisson's Ratio (ν): Ratio of lateral strain to axial strain in the elastic region

Stress-Strain Diagram Characteristics for Mild Steel and Tor Steel

• Mild Steel: Shows a distinct yield point, ductile behavior, and a gradual strain-hardening region
• Tor Steel: Higher ultimate strength and yield strength compared to mild steel

Generalized Hook's Law

• Defines the relationship between stress and strain for isotropic materials
• States that stress components are directly proportional to strain components
• This relationship is governed by the elastic constants

Factor of Safety

• Ratio of ultimate strength to allowable stress
• Used to ensure structural integrity and prevent failure

Uniaxial Stresses and Strains

• Uniaxial Tension: Force acting in one direction, stretching the material
• Uniaxial Compression: Force acting in one direction, compressing the material

Compound Bars

• Bars made of different materials joined together
• Stresses and strains are distributed based on material properties
• Can be used to manage stress and strain in structures

Temperature Stresses

• Changes in temperature cause expansion or contraction in materials
• Restrained bars experience stress due to temperature changes
• Temperature stresses can be calculated using the coefficient of thermal expansion

Compound Bars and Temperature Stresses

• Compound bars made of different metals with different thermal expansion coefficients
• Can experience additional stresses due to temperature changes
• Calculating temperature stresses in compound bars requires considering the individual properties of each metal and the geometry of the bar