جستجوی مقالات مرتبط با کلیدواژه "مخزن کروی" در نشریات گروه "مکانیک"

Functionally Graded (FG) materials are inhomogeneous composites, usually made from a mixture of metals and ceramics, providing the specific benefits of both the constituents. These materials have some unique properties such as high strength under thermomechanical stresses, lack of stress concentration and delamination. Present study is concerned with determining the alternating temperature, stress and strain fields in an FG hollow sphere subjected to cyclic thermal loading and internal pressure. The inner surface of the sphere is considered to be made of alumina grading with power law up to the outer surface made from aluminum. Duhamel's principle is utilized to calculate the temperature field in the sphere since it is appropriate in analyzing the behavior of structures with alternating boundary conditions. By considering a quasi-static condition, the governing differential equation is solved by using discretization method. The results are compared with those obtained using finite element method and good agreement is observed. The effect of frequency of the thermal load on the amplitude of the stresses is also investigated. The results show that, there is a critical range of the frequency in which the amplitude of stresses become maximum and beyond this range, the stress and strain domain vanish. It has been shown that by increasing the thickness of the sphere, the critical frequency decreases significantly.

Free hydroelastic coupled vibration analysis of frictionless liquids with a free surface in spherical tanks with a flexible bottom has been performed. The side wall has been considered to treate as a rigid body. The flexible bottom treats as a membrane at a certain distance bellow the center point, and the free surface is considered as a cross cutting at the top of the center point. The spherical coordinate system is adopted to derive the governing coupled equations, and finally a vibration analysis is carried out, using the traditional Galerkin's method, leading to closed-form solutions. Effects of various system parameters, i.e., membrane tension, liquid density, geometric parameters of the system such as the container radius, free surface distance discriminate parameter, and bottom distance discriminate parameter on the vibration behavior are investigated. The novelty of the present work is to obtain direct formulas for hydroelastic coupled vibration analysis of the mentioned system, which can be easily used in engineering design applications. Coupling between two mode numbers can be clearly seen in results, in other words, there is a coupling between vibration modes as interaction in spherical geometry.