caa a22 4500 605466513 CHVBK 20210128100307.0 cr unu---uuuuu 210128e20150301xx s 000 0 eng 10.1007/s00397-014-0824-9 doi (NATIONALLICENCE)springer-10.1007/s00397-014-0824-9 Single-point parallel disk correction for asymptotically nonlinear oscillatory shear [Elektronische Daten] [N. Bharadwaj, Randy Ewoldt] We derive exact single-point corrections for parallel disk measurements of all four asymptotically nonlinear measures under strain-controlled oscillatory shear. In this regime, sometimes called medium-amplitude oscillatory shear (MAOS), the derivatives appearing in the general stress correction are constant over the range of interest. This enables an exact single-point correction of all four shear stress components and material functions in the asymptotically nonlinear regime. This greatly simplifies the data processing and allows convenient measurements of true nonlinear material functions with parallel disk geometries. We use a strain amplitude expansion for the stress response, introducing a general non-integer strain amplitude scaling for the leading order nonlinearity, σ ∼ γ α , where typically α = 3 has been assumed in the past. The stress corrections are a multiplicative amplification by a factor f α = α + 3 4 $f\left (\alpha \right )=\frac {\alpha +3}{4}$ , shown for the first time for all four asymptotically nonlinear coefficients. Experimental measurements are presented for the four asymptotically nonlinear signals on an entangled polymer melt of cis-1,4-polyisoprene, using both parallel disk and cone fixtures. The polymer melt follows a cubic (α = 3) strain amplitude scaling in the MAOS regime. The theoretical corrections indicate a 50 % amplification of the apparent signals measured with the parallel disk fixture. The corrected (amplified) signals match the measurements with the cone. Springer-Verlag Berlin Heidelberg, 2015 Parallel disk rheometry nationallicence Single point correction nationallicence Asymptotically nonlinear rheology nationallicence Large amplitude oscillatory shear nationallicence Uncertainty propagation in MAOS nationallicence MAOS nationallicence Bharadwaj N. Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, 61801, Urbana, IL, USA aut Ewoldt Randy Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, 61801, Urbana, IL, USA aut Rheologica Acta Springer Berlin Heidelberg 54/3(2015-03-01), 223-233 0035-4511 54:3<223 2015 54 397 https://doi.org/10.1007/s00397-014-0824-9 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00397-014-0824-9 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Bharadwaj N. Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, 61801, Urbana, IL, USA aut NATIONALLICENCE 700 1- Ewoldt Randy Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, 61801, Urbana, IL, USA aut NATIONALLICENCE 773 0- Rheologica Acta Springer Berlin Heidelberg 54/3(2015-03-01), 223-233 0035-4511 54:3<223 2015 54 397