摘要:

Residual stress development in heterogeneous or composite materials is an important problem in manufacture process modeling. Composites possess an intricate microstructure in which the mismatch in thermal expansion coefficients between the fiber and matrix can lead to residual thermal stresses upon part cool-down. It is commonly assumed that prior to cool-down, the entire composite at both micro and macro length scales is at a zero stress temperature. As cool-down initiates, the mismatch in thermostress behavior and the mismatch in viscoelastic time-dependent behavior of the two phases lead to built-in residual stresses in the final product. A novel finite element approach is presented here for the coupled thermovisoelastic analysis of polymer-matrix composite structures containing microscopic heterogeneities. Due to its inherent advantages over other techniques, the asymptotic homogenization approach is employed to obtain the homogenized properties for use in the macroscale problem. For illustration, a simple Kelvin-Voight viscoelastic solid is studied to demonstrate the formulations involved in similar materials for which the time-dependent stress-strain relationship is subsequently homogenized. The formulation accounts for the dissipative corrector behavior for heterogeneous viscoelastic materials. An analytical solution for the degenerative homogeneous viscoelastic material subject to uniform thermal relaxation is employed to verify part of the formulations. Additional examples are shown to further illustrate the approach for more complex scenarios.

ISSN:0149-5739    

DOI:10.1080/01495730050192374

出版商:Informa UK Ltd    

年代:2000

数据来源: Taylor

摘要:

Thermal stresses generated within a thin plate as a result of a fast heating rate are investigated numerically using the dual-phase-lag heat conduction model. The quantitative and qualitative predictions of the dual-phase-lag model for the thermal stresses are compared with the predictions of the diffusion (parabolic) and wave (hyperbolic) heat conduction models. It is found that the predictions of the three models differ in the early stages of the heating process and then give almost the same predictions as they approach the steady-state limit.

ISSN:0149-5739    

DOI:10.1080/01495730050192383

出版商:Informa UK Ltd    

年代:2000

数据来源: Taylor

摘要:

Thermally excited vibrations of composite viscoelastic two-layer beams with interfacial slip are analyzed. Geometrically linearized conditions are considered, and the Bernoulli-Euler hypothesis is applied to each layer. At the interface a linear viscoelastic slip law is assigned. The resulting sixth-order initial boundary value problem of the deflection is solved in the time domain by separating the dynamic response in a quasistatic and a complementary dynamic portions. The quasistatic solution is determined in closed form, and the remaining complementary dynamic part is approximated by a truncated modal series that exhibits accelerated convergence. Numerical results are obtained for single-span composite beams with interlayer slip by means of a time-stepping procedure based on the linear interpolation of the driving terms within the time intervals.

ISSN:0149-5739    

DOI:10.1080/01495730050192392

出版商:Informa UK Ltd    

年代:2000

数据来源: Taylor

摘要:

A boundary element formulation based on the Laplace transform method is developed for transient coupled thermoelasticity problems with relaxation times in a two-dimensional finite domain. The dynamic thermoelastic model of Green and Lindsay is selected for the present study. The Laplace transform method is applied to the time domain, and the resulting equations in the transformed field are discretized using the boundary element method. The nodal dimensionless temperature and displacements in the transformed domain are inverted to obtain the actual physical quantities using the numerical inversion of the Laplace transform method. This work considers the Green and Lindsay theory of thermoelasticity with the thermal and mechanical loading in a finite domain. The creation and propagation of elastic and thermoelastic waves in a finite domain and their effects on each other are investigated. Different relaxation times are chosen to briefly illustrate the events that take place in GL theory. Details of the formulation and numerical implementation are also presented.

ISSN:0149-5739    

DOI:10.1080/01495730050192400

出版商:Informa UK Ltd    

年代:2000

数据来源: Taylor

摘要:

In this section, publications on thermal stresses that have appeared elsewhere are listed. In order to make the list as complete as possible, authors are requested to submit two copies of their publications to the Editor-in-Chief. Publications in languages other than English should be accompanied by the English translation of their titles.

ISSN:0149-5739    

DOI:10.1080/01495730050192419

出版商:Informa UK Ltd    

年代:2000

数据来源: Taylor

ISSN:0149-5739    

DOI:10.1080/01495730050192428

出版商:Informa UK Ltd    

年代:2000

数据来源: Taylor