| Abstract: | It is shown that the disagreement between the theory and the experimental values of the variable component of the normal stresses during periodic shear is due to lack of consideration of the stiffness of the specimen and its ratio to the stiffness of the measuring device in the direction of action of the normal force (in particular, in measurements made where the instrument is of the cone-plane type). Measurements on fused low-density extrusion polyethylene (LDEP) reveal that if these parameters of the instrument and specimen are taken into account, the theory agrees satisfactorily with experiment. Details of the measurement devices are given.Presented at the Seventh Symposium on the Rheology of Polymers, April 10–14, 1972.Institute of Mechanics of Polymers, Academy of Sciences of the Latvian SSR, Riga. Translated from Mekhanika Polimerov, No. 2, pp. 321–328, March–April, 1974. |
