On necessary precautions when measuring solid polymer linear viscoelasticity with dynamic analysis in torsion. (October 2017)

• Record Type: Journal Article
• Authors: Diani, Julie; Gilormini, Pierre
• Is Part Of: Polymer testing. Volume 63(2017)
• Page Start: 275
• Page End: 280
• Publication Date: 2017-10
• Subjects: Viscoelasticity -- Dynamic analysis -- Torsion -- Solid; Polymers -- Testing -- Periodicals; Polymères -- Tests -- Périodiques; 620.1920287
• DOI: 10.1016/j.polymertesting.2017.08.025
• Languages: English
• ISSNs: 0142-9418

Abstract

Abstract: Solid polymer linear viscoelasticity in shear is often characterized by applying torsion and using the Saint-Venant 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 Saint-Venant solution. Finite element simulations allowed definition of the sample dimensions for which the Saint-Venant solution provides a good approximation, and a coefficient is given to correct the results obtained with commercial instruments when other sample dimensions are used.