Contents of Journal of Mechanical Engineering 52, 4 (2001) 


 

R. VODICKA: Boundary integral equation systems for some kinds 
of contact problems                                                      193

M. SAGA: Numerical study of random vibration of nonlinear truss 
structures (in Slovak)                                                   208

V. M. VIHAK, Y. Z. POVSTENKO, A. V. RYCHAHIVSKYY: Integration 
of elasticity and thermoelasticity equations in terms of stresses        221

E. MALENOVSKY, F. POCHYLY: Some results of computational modelling
of dynamic behaviour of journal bearings using the Bezier body           235

Abstracts



Boundary integral equation systems for some kinds of contact problems

R. VODICKA

A boundary integral equation (BIE) solution of a contact problem is presented. Two kinds of BIE systems are shown (the first-kind BIE and the second-kind BIE), using both displacement strongly singular BIE and traction hyper-singular BIE. Boundary element approaches are used to solve these systems. The paper also presents some of the numerical results of both types of BIE systems.

Numerical study of random vibration of nonlinear truss structures

M. SAGA

This study considers the solution of elastic-plastic trusses under random excitation. The hysteretic constitutive laws will be derived from Bouc-Wen's smooth differential equations model. The stochastic linearization method, the Hurtado-Barbat's linearization approach and the Monte Carlo approach are presented. Monte Carlo simulation is used to check the accuracy of the results. Results of simple truss structures under Gaussian white-noise excitation indicate that the proposed methods are adequate for the first and second statistical moments but inadequate for estimating spectral properties.

Integration of elasticity and thermoelasticity equations in terms of stresses

V. M. VIHAK, Y. Z. POVSTENKO, A. V. RYCHAHIVSKYY

Formulation and a method of integration of differential elasticity and thermoelasticity equations in terms of stresses are proposed. The existence of only three compatibility equations in terms of strains is proved, which makes it possible to formulate correctly three-dimensional elasticity or thermoelasticity problems in terms of stresses. The single-valued relationships between tractions and displacements at the body boundary are obtained. Integral equilibrium conditions for stresses as well as integral compatibility conditions for strains and displacements are found. They are pointed out to play an important part when solving direct and inverse elasticity or thermoelasticity problems.

Some results of computational modelling of dynamic behaviour of journal bearings using the Bezier body

E. MALENOVSKY, F. POCHYLY

A new theoretical approach to the modelling of dynamic behaviour of the rigid rotating shaft in real liquid is presented in this contribution. The approach is based on application of the Navier-Stokes equation. It is possible to separate the motion of a rigid body and liquid using suitable transformation relations as well as the stationary and nonstationary motions from each other. Method of control volumes is used for the analysis, and a solution is obtained in a curvilinear co-ordinate system. The Bezier body is used for description of the geometrical configuration and also for approximation of velocity and pressure functions. The combined ALE (Arbitrary Lagrange-Euler) method is used, as it is necessary to generate a new net (perform new meshing) for change of the shaft position. Some results of numerical solution of the model task using both theories are presented.