Narrow Results

An important characteristic of a fossil power plant is its ability to maintain reliability and safety of the plant against frequent start-ups and load changes. Unstable states arising during start-ups, shutdowns and load changes give rise to unsteady temperature distribution with time in steam turbine innercasing (HP/IP), which results in non-uniform strain and stress distribution. The rapid increase of temperature during starts-ups, especially, causes susceptible to failure and reduction of expected life for steam turbine components. Thus accurate knowledge of thermal stresses is required for the integrity and lifetime assessment for the turbine components. In this paper, the fatigue damage is calculated of steam turbine inner casing was calculated by combining the stress analysis based procedure and Neuber's rule. By substituting the material cyclic stress-strain relationship into the Neuber equation, the inelastic total strain range was obtained. Using this study, life consumption of steam turbine inner-casing can be obtained and a guideline for effective maintenance was proposed.

Very recently, a mechanism to the formation of rogue waves (RWs) has been proposed by the authors. In this paper, the formation of RWs in case of the complex Sharma–Tasso–Olver (STO) equation is studied. In the STO equation, one, two and three-soliton solutions are obtained. Due to the inelastic collisions, these soliton waves are fused to one. Under the free parameters constraint this behavior do occurs. The mechanism of formation of RWs is due to the collisions of solitons and multi-periodic waves (like spectral band). These RWs as giant waves, which may be very sharp or chaotic are similar to RWs in laser. The work is done here by using the generalized unified method (GUM).

In this study, the (3 + 1)-dimensional potential-Yu–Toda–Sasa–Fukuyama equation arising from the (3 + 1)-dimensional Kadomtsev–Petviashvili equation is investigated in detail by using two powerful approaches. First, the generalized resonant multi-soliton solution is generated via the simplified linear superposition principle. Second, after applying the simplest equation method, the generalized single solitary solution is extracted. The results show that the obtained solutions are perfect. The physical explanation of the obtained solutions is depicted in various 3D and 2D figures, which are used to illustrate that the interactions of resonant multi-soliton waves are inelastic. Ultimately, the study reveals that the inelastic interactions can be determined by the sign of the wave related number $k_i$.

Coupling chemomechanical yield is one of the key issues in the oxidation of metal and polymer matrix materials. In this paper, the evolving equations for fully coupled thermal–chemical–mechanical processes were derived using the theory of thermodynamics. Then, the coupled chemomechanical yield condition and flow rule were directly obtained from the evolution equations by extending the von Mises theory of plasticity. The coupled yield condition reveals that only the chemical reactions or diffusions may lead to the yield of material even without the mechanical stress, which significantly differs from the previous works. In addition, the currently proposed yield condition combined with the flow rule as a new criterion, may be applicable in predicting the durability of materials within the allowed plastic deformation resulted from time dependent diffusion and chemical reactions. Particular attention is paid to the isothermal systems and isotropic materials for simplicity. Finally, three examples on how the deformation and reaction evolves simultaneously were given to show the applications of the present theory.