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This paper reports the results of the information retrieval project PADOK‐II. This project, which began in November 1987, is being carried out by the Linguistic Information Science Group of the University of Regensburg (LIR) in cooperation with the German Patent Office (GPO) and is sponsored by the German Ministry for Research and Technology. The long‐term aim is to integrate artificial intelligence into information retrieval research without neglecting traditional information retrieval methodology. In PADOK‐II an information retrieval system is considered which indexes documents rather shallowly using free‐text or morphological components. A large‐scale retrieval test has been carried out, based on the German Patent Information System. Answers have been obtained to some 400 queries made by 10 users in simulated real‐life situations. These results have been used to attempt to answer the question: ‘How do the linguistically‐based functions of an indexing system contribute to its performance?’ As a spinoff of this test, the influence of document size and structure was studied with a view to identifying the most reasonable basic content for a German Patent Information System.

The purpose of this paper is to investigate a two dimensional problem of micropolar porous thermoelastic circular plate subjected to ramp type heating.

Three phase lag theory of thermoelasticity has been used to formulate the problem. A numerical inversion technique is applied to obtain the result in the physical domain. The numerical values of the resulting quantities are presented graphically to show the effect of porosity and dual phase lag model. Some particular cases are also presented.

The Laplace and Hankel transforms are employed followed by the eigen value approach to obtain the components of displacements, microrotation, volume fraction field, temperature distribution and stresses in the transformed domain.

This paper fulfils the need to study the two-dimensional problem of micropolar porous thermoelastic circular plate subjected to ramp type heating.

A formulation has been developed for thermo‐elastoviscoplastic finite element analyses of continuous fibre‐reinforced composite plates subject to bending loading using a generalized continuum mechanics approach. Such an approach is used to model the non‐homogeneity in a composite, which is constituted by fibres embedded in a matrix material. The present formulation computes the respective stresses occurring in each constituent so that the respective yield criterion and flow rule of each constituent may be used if there is a material yielding in any constituent. Thermo‐elastic deformation of fibre and thermo‐elastoviscoplastic deformation of matrix are considered in the present study because the yield strength of fibre is substantially higher than that of matrix in many cases. Both constituents are assumed to be isotropic so that the von‐Mises yield criterion may be used for viscoplastic yielding of matrix. As numerical examples, a parametric study is performed for thermo‐elastoviscoplastic deformations of laminated composite plates subject to thermal bending loads.

Effects of moisture and temperature on the behaviour of composite T‐joints made of carbon fibre composite (CFC) materials are investigated. T‐joints may be exposed to moisture and temperature during their service life. Under such circumstances moisture and temperature diffuse into T‐joints. As a consequence, the stiffness and strength properties of the laminates are degraded. Moreover, since the laminae in the laminate cannot deform freely, residual stresses are introduced. The analysis is carried out by the finite element method using a modified thick shell element that takes into account the hygrothermal effects. The analysis also accounts for the lamina material properties at elevated moisture concentration and temperature. Deflections are presented in the form of contours, and maximum stresses developed in the Redux layer are presented in tabular forms. Two stacking sequences with clamped boundary conditions are considered for each variation in moisture and temperature

The purpose of this paper is to formulate a model of the equations of a two‐dimensional problem with the deformation of micropolar generalized thermoelastic medium with voids under the influence of various sources in the context of the Lord‐Shulman, Green‐Lindsay theories, as well as the classical dynamical coupled theory.

The normal mode analysis was used to obtain the exact expressions of the displacement components, force stress, coupled stress, change in volume fraction field and temperature distribution. Numerical results were given and illustrated graphically when the volume source was applied.

The presence of voids plays a significant role on all the physical quantities. The value of normal displacement and normal force stress increases while the temperature, tangential force stress and the couple stress increase and then decrease due to the presence of voids. The value of all the physical quantities converges to zero with increase in distance z.

Comparisons are made with the results predicted by the three theories in the presence and the absence of material constants due to voids.

The dual-phase-lag (DPL) model is applied to study the effect of the gravity field and micropolarity on the wave propagation in a two-temperature generalized thermoelastic problem for a medium. The paper aims to discuss this issue.

The exact expressions of the considered variables are obtained by using normal mode analysis.

Numerical results for the field quantities are given in the physical domain and illustrated graphically to show the effect of angle of inclination. Comparisons of the physical quantities are also shown in figure to study the effect of gravity and two-temperature parameter.

This paper is concerned with the analysis of transient wave phenomena in a micropolar thermoelastic half-space subjected to inclined load. The governing equations are formulated in the context of two-temperature generalized thermoelasticity theory with DPLs. A medium is assumed to be initially quiescent and under the effect of gravity. An analytical solution of the problem is obtained by employing normal mode analysis. Numerical estimates of displacement, stresses and temperatures are computed for magnesium crystal-like material and are illustrated graphically. Comparisons of the physical quantities are shown in figures to study the effects of gravity, two-temperature parameter and angle of inclination. Some particular cases of interest have also been inferred from the present problem.

The purpose of this paper is to study the axisymmetric problem in a micropolar porous thermoelastic circular plate with dual phase lag model by employing eigenvalue approach subjected to thermomechanical sources.

The Laplace and Hankel transforms are employed to obtain the expressions for displacements, microrotation, volume fraction field, temperature distribution and stresses in the transformed domain. A numerical inversion technique has been carried out to obtain the resulting quantities in the physical domain. Effect of porosity and phase lag on the resulting quantities has been presented graphically. The results obtained for Lord Shulman theory (L-S, 1967) and coupled theory of thermoelasticity are presented as the particular cases.

The variation of temperature distribution is similar for micropolar thermoelastic with dual (MTD) phase lag model and coupled theory of thermoelasticity. The variation is also similar for tangential couple stress for MTD and L-S theory but opposite to couple theory. The behavior of volume fraction field and tangential couple stress for L-S theory and coupled theory are observed opposite. The values of all the resulting quantities are close to each other away from the sources. The variation in tangential stress, tangential couple stress and temperature distribution is more uniform.

The results are original and new because the authors presented an eigenvalue approach for two dimensional problem of micropolar porous thermoelastic circular plate with dual phase lag model. A comparison of porosity, L-S theory and coupled theory of micropolar thermoelasticity is made. Such problem has applications in material science, industries and earthquake problems.

The purpose of this study is to analyze the disturbances in a two-dimensional nonlocal, micropolar elastic medium under the dual-phase-lag model of thermoelasticity whose surface is subjected to an inclined mechanical load. The present study is carried out under the influence of gravity.

The normal mode technique is used to obtain the exact expressions of the physical fields.

For inclined mechanical load, the impact of micropolarity, nonlocal parameter, gravity and inclination angle have been highlighted on the considered physical fields.

The numerical results are computed for various physical quantities such as displacement, stresses and temperature for a magnesium crystal-like material and are illustrated graphically. The study is valuable for the analysis of thermoelastic problems involving gravitational field, nonlocal parameter, micropolarity and elastic deformations.

Contact problems are among the most difficult ones in mechanics. Due to its practical importance, the problem has been receiving extensive research work over the years. The finite element method has been widely used to solve contact problems with various grades of complexity. Great progress has been made on both theoretical studies and engineering applications. This paper reviews some of the main developments in contact theories and finite element solution techniques for static contact problems. Classical and variational formulations of the problem are first given and then finite element solution techniques are reviewed. Available constraint methods, friction laws and contact searching algorithms are also briefly described. At the end of the paper, a bibliography is included, listing about seven hundred papers which are related to static contact problems and have been published in various journals and conference proceedings from 1976.