Resonance phenomena in oscillatory shear rheometry: Influence of material parameters

Redel M, Walter B, Kaschta J, Steinmann P, Schubert DW (2018)

Publication Type: Conference contribution, Abstract of lecture

Publication year: 2018

Event location: Kopenhagen

Abstract

Rheological measurements are an established method for the characterisation of dynamic mechanical polymer properties. In current literature, possible restrictions to thesemeasurements by the phenomenon of resonance were evaluated by Stettin [1]. However, this paper is quiet about the influence of material parameters like stiffness or damping on the resonance phenomenon Therefore, an unfilled silicone elastomer, free of material particle interactions, is used. The cylindrical specimen are cured in a rheometer binding them firmly to the rotor. This has proven to prevent occurrence of for example wall slip [2].

The experiments conducted are frequency sweeps by means of a parallel-plate rheometer with a smooth geometry surface. Consequently, the influence of the setup, which was detected by Stettin [1], can be neglected. Resulting resonance frequencies are analysed concerning the material's damping and stiffness. Change in these parameters is realised by variation of mixture as well as addition of an additive. The resulting resonance frequencies show an explicit dependency of complex shear modulus |G*| as a measure of the stiffness. The resulting dependence in double logarithmic plot is compared with resonance frequency calculations based on oscillatory theories. Contribution of varying damping, realised by changing loss factor tan(δ), is detectable as an additional shift in resonance frequency and also discussed.

Intriguingly, the wavedata of the stress response after resonance, obtained via fast Fourier transformation, differs from the expected sinusoidal signal. The change in wavedata and aberration from the sinusoidal excitation is explained by the phenomenon of vibration isolation. Furthermore, it is correlated with the material’s parameters reasoning the different experimental outcomes caused by the change in composition. A guideline to avoid the influence of resonance on oscillatory measurements is lastly presented.

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How to cite

APA:

Redel, M., Walter, B., Kaschta, J., Steinmann, P., & Schubert, D.W. (2018). Resonance phenomena in oscillatory shear rheometry: Influence of material parameters. Paper presentation at Nordic Polymer Days 2018, Kopenhagen, DK.

MLA:

Redel, Michael, et al. "Resonance phenomena in oscillatory shear rheometry: Influence of material parameters." Presented at Nordic Polymer Days 2018, Kopenhagen 2018.

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