Uniaxial Tension Testing

A uniaxial tension test measures a material’s Young’s modulus, yield and ultimate strengths, elongation at break, and Poisson’s ratio by pulling a specimen to failure. Standard tension tests like ASTM D638, ASTM D412, and ISO 527 are run monotonically to failure at a single strain rate. Veryst frequently goes further — testing at multiple strain rates, incorporating load and unload cycles, and adding stress relaxation or creep periods — to capture the complex, time- and history-dependent behavior of polymers.

Veryst uses digital image correlation (DIC), a non-contact optical technique that provides full-field strain maps across the specimen and enables accurate strain measurement well beyond 1000% elongation, past the range of a conventional extensometer. A typical test setup for a tension test is shown below as well as a DIC video.

 

Tests We Perform

Veryst runs both standard, tension tests with customized tests with more complex load histories on thermoplastics, thermosets, elastomers, composite materials, gels, and biomaterials. We custom design test plans using our knowledge of polymer mechanics to capture the complex, time-dependent behavior of polymers, including:

• Monotonic tension tests load a specimen at a constant rate until failure (e.g. ASTM D638, ASTM D412, ISO 527). This is the baseline test for extracting modulus, yield and ultimate strength, and elongation at break, and is usually the starting point for any material characterization program.
• Cyclic tension tests load a sample to a set stress or strain, then unload the specimen at the same rate.  This is repeated at the same value or at successively higher values to measure the non-linear loading and unloading behavior in one test.
• Creep and stress relaxation tests load the sample to a set stress (creep tests) or strain (stress relaxation tests). The stress and strain are then measured over minutes to hours to understand the time-dependent response of the materials.
• Custom tests can utilize any stress or strain history, combining any of the test methods above with changes in rate, to accomplish a load history that is applicable for your material and application.

Temperature Options

These tests can generally be performed at any temperature between -100°C and 300°C. Veryst also performs select tests submerged in liquid nitrogen for material properties at cryogenic temperatures.

Talk to an Expert About Your Material Characterization Needs

Whether you are selecting a material, diagnosing an unexpected failure, validating a design, or developing inputs for analysis, Veryst can design a test program that targets the properties most relevant to your application. Talk to a Veryst expert about how custom test geometries and fixtures can help you validate your material model and support your product development, qualification, or failure analysis.