### Contents of Journal of Mechanical Engineering *52,* 5 (2001)

G. MELTZER: Possibilities and limitations in vibro-acoustic
diagnostics of machinery 261
Z. VIRAG, M. ZIVIC, I. BUDIC: A numerical method for
simulation of continuous casting solidification process 274
J. BAJKOWSKI, M. HAC: Investigation of friction and material
properties and stress analysis in disk brakes 289
E. N. AKIMOVA: Parallelization of algorithm for solving
the three-dimensional problem of elasticity 299
O. KROPAC, J. SPRINC, M. SPRINC: Variant representation
of characteristics of random pavement unevenness (in Czech) 309

# Abstracts

###
Possibilities and limitations in vibro-acoustic diagnostics of machinery

G. MELTZER

After a short survey on the object and methods of technical diagnostics,
different sources of measured diagnostic signals are explained. The
vibro-acoustic signals are more favourable than all the others. Therefore,
they are analyzed here in more detail. One of the most important possibilities
is to extract diagnostic symptoms with a high content of information by signal
processing. Also the so-called diagnostic model (i.e. the formulated relation
between condition parameters and diagnostic symptoms) is one of the topics of
this paper. Using multivariate diagnostic models (classifiers, artificial
neural networks), which can be easily combined with vibro-acoustic diagnostic
symptoms, the diagnosis can be made more exact and robust.

###
A numerical method for simulation of continuous casting solidification process

Z. VIRAG, M. ZIVIC, I. BUDIC

A simple and accurate control volume method has been developed for simulating
the solidification process in the continuous procedure of pure metal casting.
The method uses a stationary grid, while the released or absorbed latent heat
is included in the source term. The melting temperature is maintained in
control volumes in which the phase change occurs. The method was tested
against the analytical solution for the case of semi-infinite plate cooling,
and then applied to the continuous casting process. The obtained results
confirm that the method is appropriate for predictions in heat transfer
problems involving phase transformation.

###
Investigation of friction and material properties and stress analysis in disk
brakes

J. BAJKOWSKI, M. HAC

In the paper coupled thermal-structural stresses in the steady-state analysis
of elements of machines are investigated. This problem is very important in
elements under loading, working at high temperatures such as disk brakes or
engine turbine blades. The calculations were performed by using the finite
element method. The temperature distribution in the cases considered was taken
from experimental tests. The data was gathered by complex analysis of
materials with regard to physical and chemical properties. This enables to
understand better the friction phenomena appearing in machine elements such as
disk brakes.

###
Parallelization of algorithm for solving
the three-dimensional problem of elasticity

E. N. AKIMOVA

Parallelization of the algorithm for solving the three-dimensional
boundary value problem of elasticity by the boundary integral
equations method is considered.
Realization of the applied package
on the
Parallel Computer System MBC-100 is implemented.
An analysis of the efficiency of parallelization of the algorithm
with different number of i860-processors is carried out.

###
Variant representation of characteristics of random pavement unevenness

O. KROPAC, J. SPRINC, M. SPRINC

In the article, the full graphical documentation of statistical
characteristics of random pavement unevenness is proposed and justified. Its
individual components are: measured longitudinal profile of the given road
section, longitudinal profile without trend, empirical correlation function,
empirical power spectral density (PSD) in several variants. From the
last-mentioned empirical characteristics, it is possible to estimate numerical
values of free parameters appearing in their analytical models. It follows
from measurements conducted in different countries on a number of pavements of
different structural realizations and different operational destinations that
it is desirable to evaluate the above-mentioned parameters of PSD separately
for long and for short wave lengths. In the case of nonhomogeneous unevenness,
the variability of unevenness along the trace and the first distribution
function are also necessary to be evaluated. When individual greater
imperfections are present, their character and frequency are also to be added.