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Journal of Theoretical
and Applied Mechanics
4, 2, pp. 59-70, Warsaw 1966
and Applied Mechanics
4, 2, pp. 59-70, Warsaw 1966
Doświadczalne badania własności mechanicznych polichlorku winylu
Praca niniejsza miała na celu stwierdzenie pewnych faktów doświadczalnych, sprzecznych z dotychczas przyjmowanymi zależnościami, używanymi zazwyczaj w obliczeniach i opisie zjawisk sprężystego następstwa. Wymienione zjawiska, występujące w pospolitych materiałach konstrukcyjnych, takich jak stal czy żeliwo, jedynie w podwyższonych temperaturach orientacyjnie powyżej 400°C, w tworzywach sztucznych dają się wyraźnie zauważyć już w temperaturze pokojowej. Z tego względu wzięto do badań mało odporny na temperaturę techniczny polichlorek winylu, biorąc jednocześnie pod uwagę celowość zbadania tak popularnego we współczesnej technice tworzywa.
EXPERIMENTAL STUDIES ON PROPERTIES OF THE POLYVINYL CHLORIDE
The object of this paper is to show experimental results of certain phenomenon contradicting the as asumptions often made in rheological calculations. The material used in the investigation was the technical polyvinyl chloride. Though the results obtained are valid for this material only, some of the results, shown below in the form of conclusions, may be generalized to other materials as well. (1) In the polyvinyl chloride, the volumetric creep appears very distinctly. Thus, the assumption that the volumetric part of strain is perfectly elastic in case of an arbitrary material may cause significant errors. (2) The times of elastic sequence for the volumetric creep and the shear creep differ by two orders. Taking this into account one cannot generally assume in calculations the Poisson ratio as a constant number, or, which is equivalent, the rheological coefficients cannot be taken as proportional. These conclusions should be remembered in practical rheology.
EXPERIMENTAL STUDIES ON PROPERTIES OF THE POLYVINYL CHLORIDE
The object of this paper is to show experimental results of certain phenomenon contradicting the as asumptions often made in rheological calculations. The material used in the investigation was the technical polyvinyl chloride. Though the results obtained are valid for this material only, some of the results, shown below in the form of conclusions, may be generalized to other materials as well. (1) In the polyvinyl chloride, the volumetric creep appears very distinctly. Thus, the assumption that the volumetric part of strain is perfectly elastic in case of an arbitrary material may cause significant errors. (2) The times of elastic sequence for the volumetric creep and the shear creep differ by two orders. Taking this into account one cannot generally assume in calculations the Poisson ratio as a constant number, or, which is equivalent, the rheological coefficients cannot be taken as proportional. These conclusions should be remembered in practical rheology.