Stress and Strain: a Wire to Breaking Point

Also called

stress · strain · stress-strain curve · Hooke's law · Young's modulus · elastic limit · yield point · plastic deformation · ultimate tensile strength · necking · fracture point · elasticity · elastomer · elastic hysteresis · tensile stress · permanent set · प्रतिबल · विकृति · हुक का नियम · प्रत्यास्थता

Topics

• Stress is the restoring force per unit area of cross-section, F/A; strain is the fractional change in length, ΔL/L.
• Up to the proportional limit stress is proportional to strain (Hooke’s law); the slope is Young’s modulus Y.
• Up to the elastic limit, or yield point, the wire returns to its original length when the load is removed.
• Beyond the yield point the wire flows plastically: the strain grows quickly for very little extra stress.
• Unloaded from the plastic region, the wire keeps a permanent set: it never returns to its original length.
• At the ultimate tensile strength a thin neck forms; the neck carries the whole load and the wire fractures there.
• Steel has a large Young’s modulus, about 2 × 10¹¹ Pa, so the same load stretches it far less than rubber.
• Rubber has no straight-line region and its unloading curve lies below its loading curve: elastic hysteresis.
• An elastomer such as rubber returns to its original length even after large strains, though its curve is not linear.

About this model

A GLB file of about 300 KB, shown in Lably's 3D viewer and, on a phone, placed in your room with AR. Credit: Model, science and animation: Lably (built procedurally with three.js; no downloaded meshes). | CC BY 4.0. Original geometry and animation made for Lably.

More in Physics

Artificial neural networkClass 8–123D model

Astronomical sextantClass 113D model

Atwood machine apparatusClass 113D model

Ballistic pendulum apparatusClass 113D model

Balloon-and-disc air-cushion apparatusClass 113D model

B

Banked Road and Centripetal ForceClass 113D model