The stress analysis of pressurized circumferential pipe weldments under steady state creep is considered. The creep response of the material is governed by Norton’s law. Numerical and analytical solutions are obtained by means of perturbation method, the unperturbed solution corresponds to the stress field in a homogeneous pipe. The correction terms are treated as stresses defined with the help...

Devices in modern technologies often have complex architectures, dissimilar materials, and small features. Their long-term reliability relates to inelastic, time-dependent mechanical behavior of such structures. This paper analyzes a three-layer structure consisting of, from top to bottom, an elastic film, a power-law creep underlayer, and a rigid substrate. The layers are bonded. Initially, th...

During the flood development in an oil field, the creep characteristic of mudstone is one of the important factors causing casing damage. In this study, based on the theory of fractional order differential and taking into account the creep damage evolution rules, a fractional nonlinear creep-damage model is proposed to reflect the instantaneous deformation in loading processes and the accelerat...

We analyze the Rice-Ruina state and rate dependent friction model. The system consists of a block driven by a spring with constant velocity on a dry, rough surface. Our discussion is limited to the creep-like motion, when the driving velocity is small. Two regimes of motion are observed: stick-slip and steady sliding. The stability of the steady sliding depends on the model parameters. Numerica...

We analyze the Rice-Ruina state and rate dependent friction model. The system consists of one or two blocks driven by springs with constant velocity on a dry, rough surface. Our discussion is limited to the creep-like motion, when the driving velocity is small. Two regimes of motion are observed: stick-slip and steady sliding. The stability of the steady sliding depends on the model parameters....

The mathematical modeling of a gas network is a powerful tool in order to identify the behavior of system under the different conditions. The modeling can be performed both for the steady state and unsteady state conditions. It is possible to use the fluid flow basic governing equations or the electrical analogy concept for developing the model. The second approach provides a simpler and more r...

In the Present study, attempt will be made to propose a new method for prediction of long-term essential creep of concrete utilizing some short-term creep tests under high temperature. To do so, regarding the similarities between essential creep of concrete and creep in viscoelastic materials, the time–temperature equivalence relation in viscoelastic materials is evaluated for concrete. This re...

this paper discusses the performance evaluation and availability analysis of ammonia synthesis unit of a fertilizer plant. the fertilizer plant is a complex and repairable engineering system comprises of various units viz. shell gasification and carbon recovery, desulphurization, co-shift conversion, decarbonation, nitrogen wash and ammonia synthesis etc. one of the most important functionaries...

how inflation taxation affects resource allocation and welfare has received a great deal of attention. so far, this debate has been controversial. in this paper we examine how nominal money growth as a means of public finance affects resource allocation and welfare in a neoclassical endogenous growth model with leisure and money in the utility function and production externality. the present st...