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Wed, 24 Jan 2018 07:21:10 GMT
20180124T07:21:10Z

On necessary precautions when measuring solid polymer linear viscoelasticity with dynamic analysis in torsion
http://hdl.handle.net/10985/12466
DIANI, J; GILORMINI, p
Polymer testing
Solid polymer linear viscoelasticity in shear is often characterized by applying torsion and
using the SaintVenant solution when rectangular prismatic specimens are considered. It is
shown that experimental dynamic torsion tests can show a dependency of the storage
modulus and damping factor on the dimensions of the rectangular prismatic specimen when
linear temperature ramps are applied. While the discrepancy of damping factor is explained
by temperature heterogeneities and can be corrected easily by applying temperature steps,
the inconsistency of storage modulus is due to an invalid application of the SaintVenant
solution. Finite element simulations allowed definition of the sample dimensions for which
the SaintVenant solution provides a good approximation, and a coefficient is given to correct
the results obtained with commercial rheometers when other sample dimensions are used.
Sun, 01 Jan 2017 00:00:00 GMT
http://hdl.handle.net/10985/12466
20170101T00:00:00Z
DIANI, J
GILORMINI, p
Solid polymer linear viscoelasticity in shear is often characterized by applying torsion and
using the SaintVenant solution when rectangular prismatic specimens are considered. It is
shown that experimental dynamic torsion tests can show a dependency of the storage
modulus and damping factor on the dimensions of the rectangular prismatic specimen when
linear temperature ramps are applied. While the discrepancy of damping factor is explained
by temperature heterogeneities and can be corrected easily by applying temperature steps,
the inconsistency of storage modulus is due to an invalid application of the SaintVenant
solution. Finite element simulations allowed definition of the sample dimensions for which
the SaintVenant solution provides a good approximation, and a coefficient is given to correct
the results obtained with commercial rheometers when other sample dimensions are used.