Poisson's Ratio ASTM D638, ISO 527
When uniaxial force is applied, the specimen will deform not only in the direction of the force (axial) but also laterally (transverse). Poisson’s Ratio is a measure of transverse strain against axial strain when uniaxial stress is applied.
The specimen is clamped into the grips of the Instron universal tester. Two strain measuring devices are attached to the specimen, one axial and one transverse. A uniaxial force is applied at a predetermined speed.
A standard tensile bar is typically used.
A stress-strain graph is produced and Poisson’s ratio is calculated.
**Please note that this test description is intentionally generic in nature and aimed at providing a descriptive summary to enhance test understanding. Standards can be obtained from appropriate standard authorities.
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