Polypropylene is one of the most common, fastest growing and versatile thermoplastics currently used to produce tanks and chemical piping systems. Even at room temperature creep is considerable for polypropylene products. The creep behavior of strains, stresses, and displacement rates is investigated in a thick-walled cylinder made of polypropylene reinforced by functionally graded (FG) multi-w...

the pseudo-elastic behavior of shape memory alloy (sma) truss and cantilever beam are investigated. brinson’s one-dimensional material model, which uses the twinned and detwinned martensite fractions separately as internal variables, is applied in the algorithm to establish the sma stress-strain characteristics. this material model also incorporates different young’s modulus for austenitic and ...

a constitutive model based on two–dimensional unstructured galerkin finite volume method (gfvm) is introduced and applied for analyzing nonlinear behavior of cracked concrete structures in equilibrium condition. the developed iterative solver treats concrete as an orthotropic nonlinear material and considers the softening and hardening behavior of concrete under compression and tension by using...

In this study, stress and displacement functions of the three-dimensional theory of elasticity for homogeneous isotropic bodies are derived from first principles from the differential equations of equilibrium, the generalized stress – strain laws and the geometric relations of strain and displacement. It is found that the stress and displacement functions must be biharmonic functions. The deriv...

in recent years, iran has experienced high level depreciation of the nominal exchange rate (ner). the ultimate effects of such depreciation on iranian families’ welfare and income distribution have been a challenging issue among policymakers and researchers. accordingly, this study evaluates the economic effects of ner depreciation on the rice market, using spatial price equilibrium model. the ...

We study asset-pricing implications of innovation in a general-equilibrium overlappinggenerations economy. Innovation increases the competitive pressure on existing firms and workers, reducing the profits of existing firms and eroding the human capital of older workers. Due to the lack of inter-generational risk sharing, innovation creates a systematic risk factor, which we call ‘‘displacement ...

The object of our study is the one-dimensional discrete Φ 4 model. We compare two equilibrium properties by use of molecular dynamics simulations: the Lyapunov spectrum and the time dependence of displacement-displacement and energy-energy correlation functions. Both properties imply the existence of a dynamical crossover of the system at the same temperature. This correlation holds for two rat...

this paper is concerned with global analysis of a delay sveir epidemiological model in a population of varying size. by using lyapunov stability method and lasalle’s invariance principle for delay systems, we prove that when there is no endemic equilibrium, the disease free equilibrium is globally asymptotically stable, otherwise the endemic equilibrium is globally stable.