جستجوی مقالات مرتبط با کلیدواژه « plastic analysis » در نشریات گروه « مکانیک »

In this paper, an analytical solution for computing the linear plastic stresses, critical temperature and pressure in an FGM hollow cylinder under the internal pressure and temperature is developed. It has been assumed that the modulus of elasticity and thermal coefficient of expansion were varying through thickness of the FGM material according to a power law relationship. The Poisson''s ratio was considered constant throughout the thickness. The general forms of thermal and mechanical boundary conditions were considered on the inner surface. In the analysis section, the effect of nonhomogeneity in FGM cylinder was implemented by choosing a dimensionless parameter, named m, which could be assigned an arbitrary value affecting the stresses in the cylinder. Distribution of stresses in radial and circumferential direction for FGM cylinders under the influence of internal pressure and temperature gradient were obtained. Graphs of critical temperature and pressure versus radius of the cylinder were plotted. Cases of pressure and temperature loadings were considered separately. The direct method has been considered to solve the heat conduction and Navier equations. The outer pressure for all over the cylinder goes to the plastic region when ===0 and by increasing the modules of elasticity the pressure will increase. By substituting M=0 in radial linear plastic stress formula, the perfect plastic equation will yield. By putting , 0 pp rr rr r єє in radial linear plastic stress formula, it turns to the radial elastic stress.

In this paper, an analytical solution for computing the linear plastic stresses and critical pressure in a FGM hollow cylinder under the internal pressure due to non-Axisymmetric Loads is developed. It has been assumed that the modulus of elasticity was varying through thickness of the FGM material according to a power law relationship. The Poisson's ratio was considered constant throughout the thickness. The general form of mechanical boundary conditions is considered on the inside surfaces. In the analysis presented here the effect of non-homogeneity in FGM cylinder was implemented by choosing a dimensionless parameter, named m, which could be assigned an arbitrary value affecting the stresses in the cylinder. Distribution of stresses in radial, circumferential and shear directions for FGM cylinders under the influence of internal pressure were obtained. Graphs of variations of stress versus radius of the cylinder were plotted. The direct method is used to solve the Navier equations.

In many cases, a torsional shaft may be a thick-walled radially inhomogeneous cylindrical object. The hollow shafts made of functionally graded materials (FGMs) are such kind of compositions which were studied in this paper. Cylindrical FG shafts are composed of ceramic and metallic parts with power function distribution across the radial direction. The ceramic phase is isotropic elastic and the metallic phase was elastic-plastic. In this paper, the volume fraction-based elastic–plastic mixture rule of renowned Tamura–Tomota–Ozawa (TTO) was used to model the behavior of the composite material. The elasto-plastic torsion problem was modeled and solved analytically. The results were compared with the simulations of ABAQUS and the accuracy of the solutions was evaluated. Depending on the thickness and level of inhomogeneity, different modes of yielding were obtained. The results showed that plastic zone could occur at the inner or outer surfaces or simultaneously at both surfaces; even it may start in-between the thickness. Moreover, the influence of material inhomogeneity and thickness of shaft upon the plastic zone development were studied and discussed.

In this paper, an analytical solution for computing the plastic & linear plastic stresses and critical angular velocity in a FGM hollow & solid rotating disk is developed. It has been assumed that the modulus of elasticity and yield strength were varying through thickness of the FGM material according to a power law relationship. The Poisson''s ratio were considered constant throughout the thickness. In the analysis presented here the effect of non-homogeneity in FGM rotating disk was implemented by choosing a dimensionless parameter, named m, which could be assigned an arbitrary value affecting the stresses in the rotating disk. Distribution of stresses in radial and circumferential directions for FGM rotating disk under the influence of angular velocity were obtained. Graphs of variations of stress, critical angular velocity versus radius of the rotating disk were plotted. The direct method is used to solve the Navier equations.

Elastic-plastic behavior of a beam made of functionally graded mate- rial is investigated in this work. The beam is subjected to the constant axial and bending loads and the critical values of these loads for yield, collapse and elastic-plastic conditions are obtained. The variation of elastic modulus and yield strength through the height of the beam is determined with an exponential rule. The perfect plastic curve is used to model the plastic behavior of the beam. The interaction diagrams between the bending moment and axial load are obtained for both of the yield and collapse conditions. The effect of power law function on yield and collapse loads is estimated. The results are reduced to the homogeneous beam and validated with data given in the literature search.