Dynamic mechanical analysis

1. OML751 TESTING OF MATERIALS
M.KARTHIKEYAN
ASSISTANT PROFESSOR
DEPARTMENT OF MECHANICAL ENGINEERING
AAA COLLEGE OF ENGINEERING & TECHNOLOGY, SIVAKASI
karthikeyan@aaacet.ac.in

2. UNIT V OTHER TESTING
1. Thermal Testing: Differential scanning calorimetry,
2. Differential thermal analysis. Thermo-mechanical and
3. Dynamic mechanical analysis:
4. Chemical Testing: X-Ray Fluorescence
5. Inductively Coupled Plasma-Optical Emission Spectroscopy and
6. Inductively Coupled Plasma-Mass Spectrometry.

3. DEFINITIONS OF DYNAMIC MECHANICAL ANALYSIS
(DMA)
 A technique in which the sample's kinetic properties are
analyzed by measuring the strain or stress that is generated as a
result of strain or stress, varies (oscillate) with time, applied to
the sample.
 STATIC VISCOELASTICITY MEASUREMENT:
A technique in which the change in stress or strain is measured
under uniform stress or strain that remains constant across
time.

5.  The sample is clamped in the measurement head of the DMA
instrument.
 During measurement, sinusoidal force is applied to the sample
via the probe.
 Deformation caused by the sinusoidal force is detected and the
relation between the deformation and the applied force is
measured.
 Properties such as elasticity and viscosity are calculated from
the applied stress and strain plotted as a function of
temperature or time.

7.  DMA is used for measurement of various types of polymer
materials using different deformation modes.
 There are tension, compression, dual cantilever bending, 3-point
bending and shear modes, and the most suitable type should be
selected depending on the sample shape, modulus and
measurement purpose.

8. • Viscoelastic properties such as:
-Storage modulus: E', G' (purely elastic component)
-Loss modulus: E", G" (purely viscous component)
-Loss tangent: tanδ (=E"/E'),
can be measured by DMA, and their dependence on
temperature and frequency can be analyzed.

9.  Analysis of the glass transition temperature and
temperature dependence of the modulus can be measured
by the temperature dispersion measurement.
 By performing simultaneous measurement of
temperature dispersion and frequency dispersion,
relaxation phenomena such as glass transition, side-chain
relaxation and local mode relaxation can be observed.
 This approach allow us to obtain information about
molecular structure and molecular motion of polymers.