310105i Solids 2018 TF

Elasticity

A solid's tendency to flex or deform under an external force.

Stress

The external loading force over a specific area, symbolized as sigma (σ) and measured in pascals (N/m²) or psi.

Strain

The amount of deformation from compression or tension per unit length, unitless, symbolized as ε.

Hooke's Law

The principle stating that stress is proportional to strain.

Young's Modulus of Elasticity

The slope of the stress-strain curve, representing the relationship between stress and strain.

Elastic Limit

The deformation limit where a solid recovers after the removal of an external force.

Yield Point (Strength)

The point on the stress-strain curve where a solid begins to deform plastically.

Ultimate Strength

The greatest stress that a solid can withstand before fracturing.

Breaking Strength

The exact point on the curve where fracture takes place.

Safe Working Stress

The maximum stress a solid can carry safely, also known as allowable stress.

Factor of Safety

The ratio of strength to allowable stress.

Stress Formula

Stress (σ) is defined as the loading force (F) divided by the area (A); σ = F/A.

Tension and Compression

Tension refers to pulling force, while compression refers to pushing force acting on a solid.

Strain Formula

Strain (ε) is defined as the change in length (ΔL) per unit original length (Lo); ε = ΔL/Lo.

Example of Strain Calculation

A 100m power line is stretched to 100.1m, resulting in a strain of ε = 1.0 x 10^-3.