Tensile strength

Tensile strength is determined by standardised tensile tests. A standardised specimen is subjected to a continuously increasing tensile force until it breaks. The maximum tensile stress that the material withstands is referred to as its tensile strength.

Procedure of a tensile test:

• Specimen preparation: a standardised specimen (e.g. to DIN 53504) is prepared.

• Clamping: the specimen is clamped in a tensile testing machine.

• Loading: an even tensile force is applied while the elongation of the specimen is measured.

• Result: the maximum tensile force divided by the cross-sectional area of the specimen gives the tensile strength.

Tensile strength depends strongly on the type of material:

Material	Tensile strength	Example applications
Rubber (natural rubber, NR)	15 to 25 N/mm²	Tyres, seals
Plastics (e.g. PVC, PE)	10 to 80 N/mm²	Packaging, components
Metals (e.g. steel, aluminium)	200 to 2,000 N/mm²	Mechanical engineering, construction
Composites	500 to 2,000 N/mm²	Aerospace, automotive engineering

The tensile strength of a material is determined by various factors:

• Material composition: pure metals, elastomers or polymers have different mechanical properties.

• Manufacturing process: heat treatment, vulcanisation or extrusion can change tensile strength.

• Temperature: high temperatures can reduce strength, while low temperatures can increase it.

• Fillers: in rubber and plastics, fillers such as carbon black or glass fibres can improve strength.

Tensile strength is a decisive parameter in many industries and applications:

Rubber industry

• Tyres: high tensile strength ensures stability and abrasion resistance.

• Seals: materials with high tensile strength withstand mechanical loads and ensure tightness.

Plastics industry

• Components: tensile strength is crucial for engineering plastic applications such as housings or trim.

• Films: flexible, tear-resistant materials prevent tearing under load.

Metal industry

• Construction: steel beams and other components require high tensile strength for safe structures.

• Mechanical engineering: high strength is required to bear high loads and tensile forces.

Composites

• Aerospace: high tensile strength at low weight is crucial for components such as wings and structural parts.

• Automotive engineering: light but high-tensile materials improve safety and efficiency.

Optimising tensile strength brings challenges:

• Material costs: high-strength materials are often more expensive.

• Compatibility: high tensile strength can limit the flexibility of a material.

• Process requirements: producing high-strength materials often requires elaborate processes.

• How does tensile strength differ from elongation at break? Tensile strength measures the maximum stress before the material breaks, while elongation at break describes how far a material can stretch before breaking.

• Why is tensile strength important? It indicates how much load a material can bear before it fails.

• Which materials have the highest tensile strength? Carbon fibre composites and certain steels offer the highest tensile strength.

• How can tensile strength be improved? By optimising the material composition, fillers or manufacturing processes such as heat treatment.

Tensile strength is a fundamental parameter for evaluating the mechanical properties of a material. It plays a decisive role in design, manufacturing and quality control and ensures the reliability and longevity of components in a wide range of industries. Precise knowledge and optimisation of tensile strength make a significant contribution to the development of innovative, high-performance products.