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101.
Three-dimensional analytical solution for a rotating disc of functionally graded materials with transverse isotropy 总被引:1,自引:0,他引:1
Jiangying Chen Haojiang Ding Weiqiu Chen 《Archive of Applied Mechanics (Ingenieur Archiv)》2007,77(4):241-251
Based on the basic equations for axisymmetric problems of transversely isotropic elastic materials, the displacement components
are expressed in terms of polynomials of the radial coordinate with the five involved coefficients, named as displacement
functions in this paper, being undetermined functions of the axial (thickness) coordinate. Five equations governing the displacement
functions are then derived. It is shown that the displacement functions can be found through progressive integration by incorporating
the boundary conditions. Thus a three-dimensional analytical solution is obtained for a transversely isotropic functionally
graded disc rotating at a constant angular velocity.The solution can be degenerated into that for an isotropic functionally
graded rotating disc. A prominent feature of this solution is that the material properties can be arbitrary functions of the
axial coordinate. Thus, the solution for a homogeneous transversely isotropic rotating disc is just a special case that can
be easily derived. An example is finally considered for a special functionally graded material, and numerical results shows
that the material inhomogeneity has a remarkable effect on the elastic field. 相似文献
102.
Transversely isotropic viscoplasticity model for a directionally solidified Ni-base superalloy 总被引:2,自引:0,他引:2
A transversely isotropic continuum viscoplasticity model has been formulated to capture the fatigue and creep responses of a directionally solidified (DS) polycrystalline Ni-base superalloy used mainly in turbine blades. This model has been implemented as an ABAQUS User MATerial (UMAT) subroutine using a semi-implicit integration scheme. Isothermal uniaxial fatigue data from tests conducted with and without hold times and creep data are used to characterize the stress–strain response at temperatures ranging from 427 °C to 1038 °C. The scheme leads to reduction of the associated computational costs when compared to a crystal viscoplasticity model that explicitly considers 3-D grain structure. The macroscopic elastoviscoplastic model is shown to simulate the homogenized deformation response of the polycrystalline DS alloy for various isothermal histories. The predictive capability of this model is verified using both in-phase and out-of-phase TMF data, and is compared to the results of analysis of a single crystal in terms of stress concentration and stress distribution for a model problem of a plate with a central hole. 相似文献
103.
104.
In a semiinfinite cylinder composed of anisotropic linearised elastic material, loaded on the base and clamped along the lateral surface, it is known that the solution as measured, for example, by the strainenergy flux through a plane crossection decays longitudinally at most exponentially with respect to the axial distance from the base. There is, however, also a transverse radial decay of the solution, again measured for example by the strainenergy, occurring from the region close to the cylinder's axis to the region near the lateral surface, where the energy vanishes.This problem is considered in the present paper which discusses a circular semiinfinite cylinder and derives an estimate for the strainenergy contained in a cylindrical annulus at a given distance from the base and of variable height, and whose outer surface coincides with the lateral surface of the cylinder. It is shown that the strainenergy decays at most algebraically to zero as the inner radius of the annulus increases to that of the cylinder.Sommario. E'noto che in un cilindro semiinfinito composto da materiale elastico lineare anisotropo, caricato sulla base ed incastrato lungo la superficie laterale, la soluzione elastica, misurata, per esempio, dal flusso di energia di deformazione attraverso una sezione trasversale piana, decade con legge al più esponenziale con la distanza dalla base. C'è tuttavia, anche un decadimento radiale della soluzione, misurato, per esempio, dall'energia di deformazione che passa dalla regione vicina all'asse del cilindro a quella vicin alla superficie laterale dove l'energia si annullaQuesto problema è qui studiato. Si discute in particolare un cilindro circolare semiinfinito e si deduce una stima per l'energia di deformazione contenuta in un anello cilindrico ad una distanza assegnata dalla base e di altezza variabile, e la cui superficie esterna coincide con la superficie laterale del cilindro. Si dimostra che l'energia di deformazione decade al più con legge algebrica a zero quando il raggio interno del cilindro si avvicina a quello esterno. 相似文献
105.
The paper investigates transverse vibration of a thin annular plate clamped at its inner edge to a rigid shaft, while its
outer edge is clamped to a rigid cylinder. The shaft and the outer edge of the plate are loaded by torques of the same intensity,
but of opposite directions. The whole structure rotates at a constant angular speed. The solution has been determined using
Galerkin’s method. The obtained results illustrate the impact of the torque, angular speed and inner and outer radia ratio
to transverse asymmetric vibration frequency of the plate. Stability of the plate has been examined and critical values of
angular speed and torque leading to the loss of stability of the plate have been determined. Some mode shapes have been drawn
and the influence of torque and angular speed on nodal lines has been shown. 相似文献
106.
Finite torsion and axial stretch of a long, hyperelastic, compressible and circular tube is studied for the design of a prototype of small diameter vascular prosthesis. The analysis is carried out in the context of the finite elasticity theory by using a class of Ogden strain energy function augmented with unidirectional reinforcing that is characterized by a single additional constitutive parameter for strength of reinforcement. The highly non-linear differential equations with variable coefficients governing the problem are solved numerically using a Runge–Kutta method. For different prestresses supported by the tube, the effects of the combined deformation on the stress distributions are presented. 相似文献
107.
The sensitivity of a commercial torque transducer under oscillatory shear conditions is extended by about a factor 3–5 into
the small torque region. This increased sensitivity is a result of a straightforward data treatment in the time domain termed
“on the fly oversampling”. This method is enabled by the emergence of modern ADC-cards. The underlying ideas of oversampling
together with a first experimental verification of this method are described in detail.
Received: 22 August 2000 Accepted: 14 November 2000 相似文献
108.
三峡库区巴东组地层的发育特征及其空间变化规律 总被引:2,自引:0,他引:2
根据大量的野外实际观察、室内岩石标本的薄片鉴定及化学成分分析结果,作者详细论述了三峡库区巴东组地层(T2b)的发育特征及其空间变化的规律性。巴东组地层在秭归、巴东、巫山、奉节等4个地区的总厚度最小约为830m,最大约为1420m,自东而西地层总厚度具有逐渐增大的趋势。红色与灰色是巴东组地层的两大基本色调,红色系列的岩层(第二、四段),多见为碎屑或砂泥质岩类,而灰色系列的岩层(第一、三、五段),多见为碳酸盐岩类。由其发育特征可知,巴东组为典型的易滑岩组。 相似文献
109.
The poroelastic problem associated with a hollow cylinder under cyclic loading is solved. This cylinder models an osteon, basic unit of cortical bone. Both fluid and solid phases are supposed compressible. Solid matrix is modeled as an elastic transverse isotropic material. An explicit close-form solution for the steady state is obtained. Fluid flow distribution as a function of poroelastic properties and cyclic loading is discussed as it could influence bone remodeling. Strain rate of loading is shown to play a significant role in mass flux in the porous material. 相似文献
110.
An experimental technique is proposed to determine the tensile stress–strain curve of metals at high strain rates. An M-shaped
specimen is designed which transforms a compressive loading at its boundaries into tensile loading of its gage section. The
specimen can be used in a conventional split Hopkinson pressure bar apparatus, thereby circumventing experimental problems
associated with the gripping of tensile specimens under dynamic loading. The M-specimen geometry provides plane strain conditions
within its gage section. This feature retards necking and allows for very short gage sections. This new technique is validated
both experimentally and numerically for true equivalent plastic strain rates of up to 4,250/s. 相似文献