• فهرس المقالات Thick-walled sphere

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        1 - Hygrothermal Creep and Stress Redistribution Analysis of Temperature and Moisture Dependent Magneto-Electro-Elastic Hollow Sphere
        M Saadatfar
        In this article, the time-dependent stress redistribution analysis of magneto-electro-elastic (MEE) thick-walled sphere subjected to mechanical, electrical, magnetic and uniform temperature gradient as well as moisture concentration gradient is presented. Combining cons أکثر
        In this article, the time-dependent stress redistribution analysis of magneto-electro-elastic (MEE) thick-walled sphere subjected to mechanical, electrical, magnetic and uniform temperature gradient as well as moisture concentration gradient is presented. Combining constitutive equations of MEE with stress-strain relations as well as strain-displacement relations results in obtaining a differential equation in which there are the creep strains. At the first step, discounting creep strains in the mentioned equation, an analytical solution for the hygro-thermo-magneto-electro-elastic behavior is achieved at the initial state. After that, the creep stress rates can be achieved by keeping only the creep strains in the differential equation for the steady-state condition. The analysis is done by applying the Prandtl-Reuss equations as well as Norton’s law in creep behavior modeling. Finally, the history of stresses, displacement as well as magnetic and potential field, at any time, is achieved using an iterative method. Results show that the increase in tensile hoop stress resulted from creep progress must be considered in design progress. Also, the effect of hygrothermal loading is more extensive after creep evolution. تفاصيل المقالة
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        2 - Fluidity Onset Analysis in FG Thick-Walled Spherical Tanks under Concurrent Pressure Loading and Heat Gradient
        منصور عسگری علی پرویزی شهریار علی کرمی
        In this paper,fluidity onset analysis in FG thick-walled spherical tanks under concurrent pressure loading and heat gradient has been presented. Designing thick-walled spherical tanks under pressure as tanks holding fluids under heat loads with high heat gradients requi أکثر
        In this paper,fluidity onset analysis in FG thick-walled spherical tanks under concurrent pressure loading and heat gradient has been presented. Designing thick-walled spherical tanks under pressure as tanks holding fluids under heat loads with high heat gradients require new approaches. Under high internal pressure and high temperature, the tank enters the plastic stage in a part of its thickness; hence, for designing, a tank, which necessitates the onset of fluidity, is required for pressure study and heat gradient. Elasticity module, tensile yield, heat flow coefficient and heat expansion coefficient change gradually and, according to the power model, along radial direction. In order to describe the material behavior in the plastic area in the FG thick-walled spherical tank under internal pressure and heat gradient, Treska yield index has been used, and materials’ behavior has been assumed to be in elastic-plastic form. تفاصيل المقالة