Dynamic Mechanical Analysis (DMA) is a technique used to measure the mechanical properties of a wide range of materials.
Many materials, including polymers, behave both like an elastic solid and a viscous fluid, thus the term viscoelastic. DMA measures the viscoelastic properties using either transient or dynamic oscillatory tests. The most common test is the dynamic oscillatory test, where a sinusoidal stress (or strain) is applied to the material and the resultant sinusoidal strain (or stress) is measured. The phase difference between the two sine waves is indicated as “delta”.
DMA measures viscoelastic moduli, storage modulus and loss modulus, damping properties and tan delta of materials as they are deformed under a period (sinusoidal) deformation (stress or strain).
It can be used to evaluate other properties of polymers, like glass transition, crystallinity and cross-linking effects, fatigue and other time-dependent effects.