摘要:

A thermoelastic optimization procedure is proposed for the design of symmetric. laminated, fiber-reinforced plates. A maximum stiffness criterion is employed, wherein the ply orientations are found by minimizing the complementary strain energy. Approximate solutions for the thermoelastic response are obtained using the Rayleigh-Ritz procedure. Optimization is performed via a quasi-Newton method, with the initial point selected using a random jump routine. Numerical results are presented for simply supported plates subject to a temperature distribution that varies linearly in the thickness direction. Results are given for various composite materials, and the optimum thermoelastic solutions are compared with designs for mechanically loaded laminated plates.

ISSN:0149-5739    

DOI:10.1080/01495738508942219

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

It is shown that in linear homogeneous isotropic thermoelasticity with two relaxation times the disturbances produced by an instantaneous concentrated source of heat in an infinite region represent a wave of order n = −1 with respect to the displacement u and temperature θ, i.e., 1 *uand 1 * θ, where * denotes convolution with respect to time, suffer jump discontinuities across a propagating spherical surface. Proof of the assertion is based on analysis of an exact series solution to a central initial boundary value problem of the theory. Also, closed forms of the decaying with lime displacement and temperature “amplitudes” of order 1.0 and +1 and hence closed forms of the radial and hoop-stress jumps are obtained. A way to weaken the strong discontinuity thermoelastic wave by improving the smoothness in time of the concentrated source of heat is discussed.

ISSN:0149-5739    

DOI:10.1080/01495738508942220

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The subject of this investigation is stress, displacement, and plastic strain in a centrally heated elastic‐plastic disk. The material is assumed to obey Tresca's yield criterion and its associated flow rule and to exhibit linear strain hardening. Due to the loading under consideration, plastic flow sets in at the center of the disk in a “corner-regime” of Tresca's hexagon, and, as in related cases, the plastic core is composed of two parts, the outer lying in a “side-regime.” For a special hardening parameter, explicit expressions for stress, displacement, and plastic strain are derived. With increasing core temperature, a second plastic zone forms at the edge of the disk.

ISSN:0149-5739    

DOI:10.1080/01495738508942221

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

An iterative and incremental procedure for extending linear elastic thermal‐shock vibrational solutions into the plastic region of elastoplastic materials is shown for beams. Only solutions to linear equations of motion are required. Nonlinearity is shifted into a fictitious “temperature‐moment” loading in complete analogy to the temperature loading itself. The problem of thermally induced vibrations in beams is extended to a yielding beam that in the initial state is preloaded statically in pure bending. Thermal shock is considered with nonlinear and (approximate) linear temperature distribution.

ISSN:0149-5739    

DOI:10.1080/01495738508942222

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

This paper is concerned with buckling of an initially stress‐free, elastic plate subjected to a nonuniform temperature field. The novelty of the presentation given here consists, first, of the derivation of the infinite set of algebraic equations that is associated with the buckling matrix, for a temperature field that produces a combined action of plane compressive, tensile, and shear thermal stress within a simply supported rectangular plate, and, second, in the devise of a procedure that establishes explicit closed‐form approximate solutions for the stability boundary. The technique is not restricted to simply supported or rectangular plates. In contrast to the well‐known Routh‐Hurwitz criterion, the technique employs standard criteria in the theory of algebraic functions that, together with elementary symmetric operations on the matrix, provide a maximum number of stability conditions in a fairly decomposed form, already. Closed‐form stability boundary representations are given for two‐dimensional temperature fields that produce combined compression, tension, and shear as welt as for temperature fields without shear and one‐dimensional temperature fields. Illustrative examples are discussed. The derivation of the closed-form representation of the stability boundary is presented in the Appendix.

ISSN:0149-5739    

DOI:10.1080/01495738508942223

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The flow of a thermoviscous body at elevated temperature under gravity is described by the mass, momentum, and energy balances of an incompressible, homogeneous, heat conducting, nonlinearly viscous fluid, in which the shear response includes a strongly temperature‐dependent rate factor. A scale analysis and coordinate stretching, appropriate for flows down an inclined surface, reflect the properties that depth‐to‐length ratios are different in both the “downhill” direction and perpendicular to it and that the flow is essentially from higher altitudes to lower ones. The normalized energy equation shows that, for the applications considered, in‐plane and out‐of plane (transverse) advections are important and that transverse diffusion and dissipation are both significant. Analogously, the stress‐deviator‐stretching relationship exhibits a conspicuous temperature dependence. Hence, there is strong ther-momechanical coupling.

ISSN:0149-5739    

DOI:10.1080/01495738508942224

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Thermal buckling of load-free supported plates is considered. Especially the influence of the distribution of the applied temperature field on buckling modes and proper values is investigated, ft turns out that fields of temperature‐shock type are most critical and lead to the lowest proper values of buckling.

ISSN:0149-5739    

DOI:10.1080/01495738508942225

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

After a brief summary of the general frame for the definition of constitutive laws of coupled thermomechanical processes, a formulation of a constitutive law for a particular material is introduced. This law is then applied to the uniaxial tension test using the finite element method. Theoretical and experimental results are compared. A particular investigation of the necking problem is presented.

ISSN:0149-5739    

DOI:10.1080/01495738508942226

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

ISSN:0149-5739    

DOI:10.1080/01495738508942227

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor