Elastic limit

The yield strength represents the maximum stress that a material can undergo before exhibiting permanent deformation. It is an essential mechanical parameter for evaluating the strength, rigidity and durability of a product or component.

This value is determined during a tensile or compression test , according to ISO 527 for polymer materials. The analysis makes it possible to identify the transition between the elastic phase (reversible) and the plastic phase (irreversible), ensuring control of mechanical properties during dimensioning , quality control or formulation .

Principle of measurement

In testing, a sample is subjected to increasing stress until the strain is no longer proportional to the applied load.
The yield stress (Re) is then defined as the stress at which the material ceases to behave elastically .

The test is carried out using a dynamometer or a tensile testing machine , equipped with a force sensor and an extensometer. The parameters measured include:

• the yield stress (Re) ,
• modulus (E) ,
• the rupture deformation ,
• and sometimes tenacity (energy needed to break).

These data are essential for evaluating the performance of materials used in packaging, polymers, technical components or finished products .

For additional analyses, also discover:

• tensile testing to measure strength and elongation at break,
• the bending test to determine the deformation rigidity,
• and compression testing to assess strength under load.

Industrial applications

The measurement of the elastic limit applies to a wide variety of materials and sectors:

• Materials and polymers : control of the mechanical resistance of plastics, composites and elastomers for molding or extrusion.
• Packaging : checking the strength of films, trays, caps or containers subject to mechanical stress.
• Cosmetics and pharmaceuticals : study of the resistance of primary and secondary packaging (bottles, tubes, lids).
• Food and nutraceuticals : validation of packaging intended for food contact or liquid and solid supplements.
• Plant and bio-sourced materials : characterization of the mechanical strength of biopolymers and ecological alternatives.

This analysis guarantees the compliance of materials with industrial standards , while ensuring their performance under real-life usage conditions.

Analytical interest and complementarity

The study of the elastic limit is often coupled with other mechanical or thermal analyses to fully characterize the behavior of the material:

• Melt Flow Index (MFI) to relate polymer viscosity to its mechanical properties,
• DSC thermal analysis to observe melting and crystallization transitions,
• TGA analysis to assess thermal stability,
• FTIR infrared spectroscopy to check chemical composition,
• Accelerated aging test to observe the evolution of mechanical properties over time.

These combined approaches provide a complete characterization of the material , from its molecular structure to its final mechanical performance.

YesWeLab Services

YesWeLab provides a network of ISO 17025 and/or COFRAC , specialized in mechanical and rheological testing .
Our experts define the experimental protocol adapted to your matrix (plastic, metal, composite, biopolymer) and interpret the results according to regulatory and industrial requirements.

Thanks to the YesWeLab digital platform , you can centralize your analysis requests, track your samples and access your results reports online.
Since 2020, YesWeLab has been supporting players in the packaging, polymers and technical materials sectors in their resistance and mechanical performance studies.

To obtain a quote or a personalized analysis solution, contact our scientific team today.