caa a22 4500 465814123 CHVBK 20180323112123.0 cr unu---uuuuu 170327e19900701xx s 000 0 eng 10.1007/BF01339883 doi (NATIONALLICENCE)springer-10.1007/BF01339883 On the relaxation of shear and normal stresses of viscoelastic fluids following constant shear rate experiments [Elektronische Daten] [W. Gleißle, N. Ohl] By means of a cone and plate rheometer the relaxation of the shear stress and the first normal stress difference in polymer liquids upon cessation of a constant shear rate were examined. The experiments were conducted mostly in a high shear rate region of relevance for the processing of these materials. The relaxation behavior at these shear rates can only be measured accurately under extremely precise specifications of the rheometer. To determine under which conditions the integral normal thrust is a convenient measure for the relaxing local first normal stress difference the radial distribution of the pressure in the shear gap was measured. The shape of relaxation of both the shear stress and the first normal stress difference could be closely approximated for the entire measured shear rate and time range by a two parameter statistical function. In the range of measured shear rates, one of the parameters, the standard deviationS, is equal for the shear and the normal stress, and is independent of the shear rate within the limit of experimental error. The second parameter, the mean relaxation timet′ 50,τ of the shear stress andt′ 50,σ of the first normal stress difference, can be calculated approximately from the viscosity function and only a single relaxation experiment. Steinkopff, 1990 R elaxation nationallicence f irst normal s tress difference nationallicence G aussian e rror function nationallicence s tress test nationallicence c one and plate r heometer nationallicence m irror relation nationallicence Gleißle W. Institut für Mechanische Verfahrenstechnik und Mechanik, Universität Karlsruhe (TH), 7500, Karlsruhe 1, FRG aut Ohl N. Institut für Mechanische Verfahrenstechnik und Mechanik, Universität Karlsruhe (TH), 7500, Karlsruhe 1, FRG aut Rheologica Acta Steinkopff-Verlag 29/4(1990-07-01), 261-280 0035-4511 29:4<261 1990 29 397 https://doi.org/10.1007/BF01339883 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF01339883 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Gleißle W. Institut für Mechanische Verfahrenstechnik und Mechanik, Universität Karlsruhe (TH), 7500, Karlsruhe 1, FRG aut NATIONALLICENCE 700 1- Ohl N. Institut für Mechanische Verfahrenstechnik und Mechanik, Universität Karlsruhe (TH), 7500, Karlsruhe 1, FRG aut NATIONALLICENCE 773 0- Rheologica Acta Steinkopff-Verlag 29/4(1990-07-01), 261-280 0035-4511 29:4<261 1990 29 397 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer