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Studies of relaxation phenomena in polymers. I. The use of periodic square and triangular stress functions
Author(s) -
Jansson JanFredrik
Publication year - 1973
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1973.070171004
Subject(s) - viscoelasticity , creep , square (algebra) , stress relaxation , relaxation (psychology) , function (biology) , nonlinear system , stress (linguistics) , mathematical analysis , order (exchange) , mathematics , materials science , physics , thermodynamics , geometry , quantum mechanics , psychology , social psychology , linguistics , philosophy , finance , evolutionary biology , biology , economics
In order to evolve the methods of mechanical spectroscopy and find new methods of studying the rise of nonlinear viscoelasticity, periodic square and triangular stress functions have been used. A “new” viscoelastic function is defined, log J 2 = g {log J 1 }, where J 1 and J 2 are the compliances at the time (ζ/2 + 2 n ζ) n →∞ for an odd, periodic, square function and an even, periodic, triangular function, respectively, with periods of 2ζ. The function shows characteristic shapes for viscoelastic spring and dashpot models. The interrelations between the complex compliance and J 1 and J 2 are developed; and since the sum of J 1 and J 2 at the time ζ/2 agrees very well with the creep compliance at the same time, J 1 and J 2 can be used as an interrelation between complex compliance and creep compliance. Special equipment for measuring the compliances J 1 nd J 2 is described.