Asymptotic Solution of Anisotropic Cyclic Creep Problem
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Дата
2016
ORCID
DOI
Науковий ступінь
Рівень дисертації
Шифр та назва спеціальності
Рада захисту
Установа захисту
Науковий керівник
Члени комітету
Видавець
NTU "KhPI"
Анотація
Thin-walled structural elements made from rolled metal usually demonstrate anisotropic creep behavior. Very
often the model of transversally-isotropic material is suitable for its description. Due to the difficulties in direct
numerical integration the case of cyclic loading demands the development of suitable method of the creep
problem’s solution when the material behavior isn’t isotropic.
The general problem statement as well as the constitutive equations for two-dimensional creep problem are
presented. Transversally-isotropic creep material model developed by O.Morachkovsky is used. The case of
substantial stress values which are greater than yield limit is studied. Addition of cyclic loading, which is
essentially varying the creep response, is analyzed.
Deriving of resolving system of creep equations was performed by use of the method of asymptotic
expansions jointly with the method of averaging in a period of stress cycle. This system allows simulation of
only the problem of static loading with constitutive equations of special type, in which the values of cyclic parts
of loading are included in so-called influence functions. These equations are derived from the general form by
use of asymptotic expansions of creep strain functions with further averaging in a period of oscillations.
Developed method is realized as an applied C+ + software. The Finite Element Method is used for solution
of boundary-value problem jointly with Finite Difference Scheme for initial one.
The results of experimental investigations of creep in specimens and plates with holes made from rolled
steel are discussed. The anisotropic creep curves in three directions were obtained and constants for creep flow
rule were determined. Additional number of experiments was performed for the case of cyclic loading. The
comparison between experimental and numerical data shows the satisfactory agreement. Due to this a number
of numerical examples for cyclic creep simulation in thin plates were performed and their results are discussed.
Опис
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Бібліографічний опис
Asymptotic Solution of Anisotropic Cyclic Creep Problem / D. Breslavsky [et al.] // Nonlinear Dynamics–2016 (ND-KhPI2016) : proceedings of 5th International Conference, dedicated to the 90th anniversary of Academician V. L. Rvachev, September 27-30, 2016 = Нелінійна динаміка–2016 : тези доп. 5-ї Міжнар. конф., 27-30 вересня 2016 р. – Kharkov : NTU "KhPI", 2016. – P. 276.