Modelling of Creep and Oscillations in Material Described by Armstrong-Frederick Equations
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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
Different structural elements at high temperatures and cyclic loading demonstrate essential creep behavior.
Due to variety of materials which are used in modern industrial applications the different forms of creep
response have to be analyzed. The one of them presents in materials are characterized by creep processes with
essential recovery, which is expressed by strain decreasing after the unloading. Such material behavior is
described by well-known Armstrong-Frederick model.
The case of cyclic loading leading to forced oscillations at high temperature is studied. The Armstrong-
Frederick creep model contains two equations: first for creep strain rate function as well as the second for socalled
backstress evolution. The problem is solved by two time scales methods with subsequent averaging in a
period of oscillations.
The solution was performed for the hyperbolic creep strain rate function which satisfactory describes the
high-temperature behavior of advanced steel with primary creep conditions. The stress function is presented by
expansion in Fourier series. Asymptotic solution of creep equations was obtained and by use of the procedure
of averaging in the period the new model describing ‘slow’ creep motion has been derived. The analytical
forms of influence functions for both equations of the model expressing the role of cyclical loading were
obtained.
Numerical examples which demonstrate the cyclic creep behavior in advanced steel X20CrMoV12-l are
presented and discussed.
Опис
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Бібліографічний опис
Modelling of Creep and Oscillations in Material Described by Armstrong-Frederick Equations / 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. 274.