Poisson's Ratio ASTM D638

Poisson's Ratio ASTM D638, ISO 527

Introduction Poisson's Ratio is an important material property used to understand the behavior of a material when subjected to uniaxial stress. This ratio measures the transverse strain against axial strain when a uniaxial force is applied to a specimen. When uniaxial force is applied, the specimen will not only deform in the direction of the force (axial) but also laterally (transverse).

Test Procedure

To determine the Poisson's ratio of a material, a standard tensile bar is typically used as the specimen. The specimen is clamped into the grips of an Instron Universal Tester. Two strain measuring devices are attached to the specimen - one for axial strain measurement and one for transverse strain measurement. A uniaxial force is then applied at a predetermined speed.

Data

After the test procedure, a stress-strain graph is produced and Poisson's ratio is calculated from the data collected from the strain measuring devices.

Conclusion

Poisson's Ratio is an important material property that provides insight into the behavior of a material under uniaxial stress. By conducting a simple test, engineers and researchers can determine the Poisson's ratio of a material and use that information to make informed decisions about its use and application.