Bruddstyrke

Bruddstyrke, usually translated as ultimate tensile strength (UTS), is the maximum stress a material can withstand while being stretched before it fails or fractures. It is expressed as stress, typically in megapascals (MPa), and is obtained from a tensile test in which a standardized specimen is pulled until fracture. The stress at the moment of rupture defines the bruddstyrke. It is influenced by the material’s microstructure, temperature, strain rate, and the presence of flaws.

Bruddstyrke is related to, but distinct from, yield strength. Yield strength marks the onset of permanent plastic deformation; in ductile materials the yield point occurs before fracture, with fracture (and thus bruddstyrke) occurring after necking and further plastic flow.

Measurement and standards: Bruddstyrke is determined on a universal testing machine through a tensile test on specimens with known geometry. The applied force divided by the cross-sectional area yields the stress, and the peak value before fracture is recorded as the bruddstyrke. Standards and test methods vary by material, with ISO 6892 and related ASTM standards commonly used for metals, and analogous standards for plastics and composites. In rope and cable testing, bruddstyrke is often referred to as breaking load and is determined under specified loading conditions.

Applications and limitations: Bruddstyrke is a key parameter in material selection and structural design, but it must be used with safety factors and alongside other properties such as toughness, creep, and fatigue. Real-world performance depends on flaws, environmental conditions, and long-term loading.

Typical ranges: Metals generally exhibit bruddstyrke from hundreds of MPa to over 1 GPa; polymers 20–100 MPa; ceramics can be high in MPa but brittle.